There seems to be a recurrent theme that on a seemingly random basis, mortals will "freeze": stick where they are for no reason (certainly not fear). This is using xp home on an athlon 1900 with 512mb ram and a 128mb gforce4. Is there any logic to when this happens and interim solutions - this appears to be a glitch and a patch required
This is a shame becuase otherwise the game is in a positive sense infuriating
Don't think it has anything to do with your system. It's definitely code bugs. I'd be surprised if there's not at least an attempt to clean it up some in the patch when it comes out.
For now, try to posess the "stuck" people, or alternately, drive them insane instead of scaring them off (when stuck, even if their terror bar is maxed, you can still work on 'em to get 'em to go nuts)
Either of these can sometimes fix an otherwise blown level if you can get the right ghost in range of 'em.
Gifts can be handy for this if you haven't got the correct fetter nearby...
Meow.... er, I mean... BOO! Yeah.. that must be it. >^,,^<