I guess I spoke too soon.  Poser runs but won't load or render any of the old files.  The textures library is gone from the Poser 7 runtime, including from copies made a long time ago.  I just checked a copy on a DVD made 2 months ago, even the textures library there is gone.

Up until yesterday I had used figures from the main runtime, including their textures.  No idea where the textures directory went, or how it could have disappeared even from old copies.