Hi,
I'm sorry to hear you're having problems with this. I haven't encountered anything like it before, and unfortunately haven't been able to reproduce it yet.
It looks like there's some sort of null character in your workspace that SoapUI can't read causing the crash. We need some clues in order to figure out what's going on. What version of SoapUI are you running? Is there any pattern that can be observed when this occurs? Are you working on any project in particular where this happens? If so, is it possible for you to send me the project file so that I can take a look?
Regards,
Arian
SmartBear Sweden