Error: Cannot find module 'linvodb3': tried everything, nothing works



Since yesterday morning I try to implement my linvodb3 database in electron on windows 10. When I open the app.exe I got:
A JavaScript error occurred in the main process
Uncaught Exception:
Error: Cannot find module ‘linvodb3’

I use the angular2-electron-starter seed that comes with two package.json one in root/ one in root/electron.

So far I tried:
installing linvodb3 in / and /electron (npm install linvodb3 --save)
using electron-rebuild in both directories (took me 6h to get it working)
apm install
setting var LinvoDB = require(‘linvodb3’); in index.html similar to the jQuery questions.
multiple deinstallations and installations of various packages recommended at similar questions.

Thank you so far and best regards,