I run a recorded webtest which failed. After connecting to the team project, I rightclicked the test result and clicked Create Work Item -> Bug.
When I then try to save this new work item an error meassage pops up: Error The server operation failed. (BackendArgumentException).
When I create a new work item from the Team Menu, I can save it without problems.

I did some more investigation. The problem seems to lie in the attchment. When I manually created and saved a work item, there was no attachment. When saving a new work item with attachment, it fails, with the same error message.

Is there a workaround for this problem?