I have to say that in my experience if the x86 emulator crashes in Debug mode so far it has always pointed to a bug in my code, not the emulator code that is at fault.
For example one time I was destroying a window in one thread as it was being operated on in another thread directly (i.e. it was actually accessing memory which was being deallocated mid-access). This as I'm sure you can see is a bug in my code not the emulator, since I should have shut down the thread, waited till the thread had actually terminated and them and only then destroyed the window.
However it had previously runs for weeks on many iPAQ and Toshibas without ever crashing once. The timing and maybe the lack of the memory being overridden meant it never actually crashed. However I'm sure you can see given enough future versions of Windows CE, it probably would have eventually :(
