As an additional information, I’m working in the same company as the guy with this post:
and I had the same problem, which was solved with an update of the runner. I think it could be a simillar problem because I’m not alone in my company with that error. But a colleague who works at a subsidiary has no problems with the same code. We are using all the actual versions of the OpenTap software. For the Runner I’m using the version 2.4.0-beta.2. I have to use a beta because of the bug in the mentioned post.