"Can not run RPC" - ERROR when Inventor application is embedded in our VB.Net application (HRESULT: 0x800706BE)

Previous situation: We embedded Inventor 2017 in our VB.Net application. We programmaticaly open a new document in Inventor without any problems. This works on both operating systems Windows 7 and Windows 10.

Last week we updated to Inventor 2018.

Current situation: Everything works fine on Windows 7, but on Windows 10 there is this error! Can not run RPC HRESULT: 0x800706BE.

I get it to work when i excute Inventor 2018 outside our application. For some reason it doesn't work when Inventor 2018 is embedded inside our application.

I hope the problem is clear?

Thanks in advance.