Hello all
when trying to configure OpenProject on a Debian jessie or stretch system after intalling the deb package , the process fails at the “webpack” step with the following message:

@ $(npm bin)/webpack --config webpack.production.config.js
{"openproject-translations":"/opt/openproject/vendor/bundle/ruby/2.4.0/bundler/gems/openproject-translations-f9e63ef51dc9","openproject-global_roles":"/opt/openproject/vendored-plugins/openproject-global_roles","openproject-auth_plugins":"/opt/openproject/vendored-plugins/openproject-auth_plugins","omniauth-saml":"/opt/openproject/vendor/bundle/ruby/2.4.0/bundler/gems/omniauth-saml-89eeb83517b2","openproject-auth_saml":"/opt/openproject/vendor/bundle/ruby/2.4.0/bundler/gems/openproject-auth_saml-97212abb8378","omniauth-openid-connect":"/opt/openproject/vendor/bundle/ruby/2.4.0/bundler/gems/omniauth-openid-connect-c3bce4c9e9ac","omniauth-openid_connect-providers":"/opt/openproject/vendor/bundle/ruby/2.4.0/bundler/gems/omniauth-openid_connect-providers-86f3670e127e","openproject-openid_connect":"/opt/openproject/vendored-plugins/openproject-openid_connect","openproject-documents":"/opt/openproject/vendored-plugins/openproject-documents","openproject-my_project_page":"/opt/openproject/vendored-plugins/openproject-my_project_page","openproject-xls_export":"/opt/openproject/vendored-plugins/openproject-xls_export","reporting_engine":"/opt/openproject/vendored-plugins/reporting_engine","openproject-costs":"/opt/openproject/vendored-plugins/openproject-costs","openproject-reporting":"/opt/openproject/vendored-plugins/openproject-reporting","openproject-meeting":"/opt/openproject/vendored-plugins/openproject-meeting","openproject-pdf_export":"/opt/openproject/vendored-plugins/openproject-pdf_export","openproject-backlogs":"/opt/openproject/vendored-plugins/openproject-backlogs","openproject-local_avatars":"/opt/openproject/vendored-plugins/openproject-local_avatars","openproject-webhooks":"/opt/openproject/vendored-plugins/openproject-webhooks","openproject-github_integration":"/opt/openproject/vendored-plugins/openproject-github_integration"}
Applying webpack.optimize plugins for production.
clean-webpack-plugin: /data/opt/openproject/app/assets/javascripts/bundles has been removed.
clean-webpack-plugin: 1 file(s) excluded - openproject-vendors.js
Happy[ts]: Version: 4.0.0. Threads: 4
Happy[ts]: All set; signaling webpack to proceed.
Starting type checking service...
Using 1 worker with 2048MB memory limit
ts-loader: Using typescript@2.5.2 and /data/opt/openproject/frontend/tsconfig.json
ts-loader: Using typescript@2.5.2 and /data/opt/openproject/frontend/tsconfig.json
ts-loader: Using typescript@2.5.2 and /data/opt/openproject/frontend/tsconfig.json
ts-loader: Using typescript@2.5.2 and /data/opt/openproject/frontend/tsconfig.json
Hash: 6b5a153048b54e69b6cd
Version: webpack 3.5.6
Child
    Hash: 6b5a153048b54e69b6cd
    Time: 30909ms
                                   Asset     Size  Chunks                    Chunk Names
    7b9776076d5fceef4993b55c9383dedd.gif  1.85 kB          [emitted]         
                 openproject-core-app.js  1.66 MB       0  [emitted]  [big]  core-app
                    openproject-costs.js  77.4 kB       1  [emitted]         costs
          openproject-my_project_page.js  3.05 kB       2  [emitted]         my_project_page
                openproject-core-app.css  33.6 kB       0  [emitted]         core-app
       [0] ./angular-modules.ts 5.11 kB {0} [built]
       [9] ./helpers/debug_output.ts 742 bytes {0} [built]
      [26] delegated ./node_modules/webpack/buildin/global.js from dll-reference vendors 42 bytes {0} {1} [built]
      [92] delegated ./node_modules/webpack/buildin/module.js from dll-reference vendors 42 bytes {0} {1} [built]
     [271] ./openproject-app.js 1.25 kB {0} [built]
     [272] ./init-app.js 6.16 kB {0} [built]
     [273] delegated ./app/vendors.js from dll-reference vendors 42 bytes {0} [built]
     [274] ../vendor/at.js/jquery.atwho.min.css 41 bytes {0} [built]
     [275] ../vendor/select2/select2.css 41 bytes {0} [built]
     [281] ../node_modules/angular-i18n angular-locale_(en|af|ar|bg|ca|cs|da|de|es|et|fa|fi|fr|he|hr|hu|id|it|ja|ko|lol|lt|lv|nl|no|pl|pt-BR|pt|ro|ru|sk|sv-SE|th|tr|uk|vi|zh-TW|zh).js$/ 1.17 kB {0} [built]
     [330] ./helpers/index.js 1.66 kB {0} [built]
    [1154] /data/opt/openproject/vendored-plugins/openproject-my_project_page/frontend/app/openproject-my_project_page-app.js 1.39 kB {2} [built]
    [1155] /data/opt/openproject/vendored-plugins/openproject-my_project_page/frontend/app/components ^((?!\.(test|spec)).)*\.(js|ts)$ 330 bytes {2} [built]
    [1159] /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/openproject-costs-app.js 3.12 kB {1} [built]
    [1160] /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components ^((?!\.(test|spec)).)*\.(js|ts)$ 425 bytes {1} [built]
        + 1161 hidden modules

    WARNING in /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/budget/cost-budget-subform.directive.ts
    Module parse failed: /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/budget/cost-budget-subform.directive.ts Unexpected token (34:10)
    You may need an appropriate loader to handle this file type.

    | 
    |   // Container for rows
    |   private container: ng.IAugmentedJQuery;
    | 
    |   // Template for new rows to insert, is rendered with INDEX placeholder
     @ /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components ^((?!\.(test|spec)).)*\.(js|ts)$
     @ /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/openproject-costs-app.js

...... 
some similar warnings
.....

    ERROR in /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/wp-display/field-types/wp-display-costs-by-type-field.module.ts
    Module parse failed: /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/wp-display/field-types/wp-display-costs-by-type-field.module.ts The keyword 'interface' is reserved (34:0)
    You may need an appropriate loader to handle this file type.

    | import {WorkPackageResourceInterface} from 'core-components/api/api-v3/hal-resources/work-package-resource.service';
    | 
    | interface ICostsByType {
    |   costObjectId:string;
    |   costType:{
     @ /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/openproject-costs-app.js 29:30-114

    ERROR in /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/wp-display/field-types/wp-display-currency-field.module.ts
    Module parse failed: /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/components/wp-display/field-types/wp-display-currency-field.module.ts Unexpected token (33:9)
    You may need an appropriate loader to handle this file type.

    | export class CurrencyDisplayField extends DisplayField {
    | 
    |   public isEmpty(): boolean {


|     return !this.value ||
    |       !parseFloat(this.value.split(" ")[0]);
     @ /data/opt/openproject/vendored-plugins/openproject-costs/frontend/app/openproject-costs-app.js 30:27-106
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../vendor/select2/select2.css:
         1 asset
           [0] ../vendor/select2/select2.png 861 bytes {0} [built]
           [1] ../vendor/select2/select2-spinner.gif 82 bytes {0} [built]
           [2] ../node_modules/css-loader!../node_modules/postcss-loader!../vendor/select2/select2.css 13.3 kB {0} [built]
           [4] ../vendor/select2/select2x2.png 1.17 kB {0} [built]
            + 1 hidden module
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../vendor/at.js/jquery.atwho.min.css:
           [0] ../node_modules/css-loader!../node_modules/postcss-loader!../vendor/at.js/jquery.atwho.min.css 750 bytes {0} [built]
            + 1 hidden module
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../node_modules/ng-dialog/css/ngDialog.min.css:
           2 modules
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../node_modules/ui-select/dist/select.min.css:
           2 modules
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../node_modules/jquery-ui/themes/base/core.css:
           2 modules
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../node_modules/jquery-ui/themes/base/datepicker.css:
           2 modules
    Child extract-text-webpack-plugin ../node_modules/extract-text-webpack-plugin/dist ../node_modules/css-loader/index.js!../node_modules/postcss-loader/index.js!../node_modules/jquery-ui/themes/base/dialog.css:
           2 modules
rake aborted!
Command failed with status (2): [$(npm bin)/webpack --config webpack.produc...]
/data/opt/openproject/lib/tasks/assets.rake:51:in `block (3 levels) in <top (required)>'
/data/opt/openproject/lib/tasks/assets.rake:50:in `chdir'
/data/opt/openproject/lib/tasks/assets.rake:50:in `block (2 levels) in <top (required)>'
/data/opt/openproject/lib/tasks/packager.rake:55:in `block (2 levels) in <top (required)>'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli/exec.rb:74:in `load'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli/exec.rb:74:in `kernel_load'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli/exec.rb:27:in `run'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli.rb:360:in `exec'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/vendor/thor/lib/thor/invocation.rb:126:in `invoke_command'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/vendor/thor/lib/thor.rb:369:in `dispatch'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli.rb:20:in `dispatch'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/vendor/thor/lib/thor/base.rb:444:in `start'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/cli.rb:10:in `start'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/exe/bundle:35:in `block in <top (required)>'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/lib/bundler/friendly_errors.rb:121:in `with_friendly_errors'
/opt/openproject/vendor/bundle/ruby/2.4.0/gems/bundler-1.15.1/exe/bundle:27:in `<top (required)>'
/opt/openproject/bin/bundle:3:in `load'
/opt/openproject/bin/bundle:3:in `<main>'
Tasks: TOP => assets:precompile => assets:compile_environment => assets:prepare_op => assets:webpack
(See full trace by running task with --trace)@
 

There are no system ruby nor node packages installed that should interfer
Running this step as “openproject” user in ./frontend works ok.
Installation on other Debian 8 or 9 systems produced the same problem.

Since I’am at a loss to find the error, I would appreciate any hints to solve this problem.

Thanks in advance
Ulrich