Good advice, but in this case it's a copy of V4 that was downloaded and reinstalled on June 18, 2010 & is unmodified.  (V4 & M4 were both updated last week).  As I usually only use Poser for testing, I don't keep a copy of V4 with morphs preloaded.  There was similar behaviour with these files a few weeks ago, so I'm not inclined to think its caused by the recent V4 update.