Thanks for the responses.  

Mark: I'd tried cancelling and then trying to apply the textures manually, but while the geometry came through, I couldn't even go in and add the textures manually -- an "unknown error 0" would happen.  Resetting preference is a possiblity, but as you'll see below, I did come upon a solution.

Mylemonblue (though may I call you "face of Mars?"), that's some crazy info, but really good to know.  Poser, having been around for about a billion years and apparently not throwing out any of its old code, has some strange quirks.  That's one that's really good to know.  It doesn't seem to have been my problem, though.

As it turns out, it appears I have to be working in XP as an administrator.  I switched to the admin account (which is necessary when working in Poser and attemping to save characters to my library, but had never been an issue in Carrara) and eureka! the textures imported.  The fact that Poser requires you to run as an administrator in XP is nearly unforgivable as being logged on as an adminstrator opens you up to viruses, worms, etc.  (No admin priviledges means malware can't install itself, unless it's really sophistocated malware.)  Though I do run with protection (safe surfing for me!), you can never be too careful.

Anyway, it seems that the mystery is solved.  Thanks for the suggestions, though!

 - Dex