there are alot of bugs, this is true. these unhandled exception usually occur because a filename has been changed, or contains special characters.
i have been sticking with efpse despite the bugs, and learning how to avoid these types of errors as much as possible.
but i do understand your frustration. good luck.
have you tried coppercube? it is much less buggy but also not as easy to use or intuitive. it is still probably the easiest "general use" 3d engine.