I have the same problem but only when playing MP4 video on MPC-HC (latest v. 1.5.XXX). Did not have this problem before with the old MPC. If I remux the MP4 video into MKV format or TS format, everything works perfectly fine. So the problem seems to be between MPC-HC and the MP4 format itself.
im on win 7 ultimate and when im watching a video and i fast forward or whatever it freezes and a window pops up and says (media player classic ran into a problem and needs to close)
Is this a common problem with the HM version because i never had this problem with the normal mpc