It doesn't have the proper iscripts, I would bet. Please--before posting, read the stickied topics at the top thoroughly. They make things easier for all of us. And please, restrain your enthusiam for emoticons. One emoticon at a time is perfectly sufficient.
That said, the unit probably can't find frames the iscript tells it to use and crashes because of it. With the SCV, it might have to do with mining behavior.