o.k., it sounds pretty bad.  it may be:

1. bad install of carrara app
2. bad car file containing hiro animation
3. bad prefs.  check them again.  I dunno where the scratch disk or multiple undo
   is in the vista version, so you'll hafta read all the prefs to find 'em.  once found,
   post screen shots of 'em. 

2 things to try:

1. open c6pro, go to browser/scenes/animation and try those, e.g. ghost.
   if they render to the end, then c6pro app may be o.k..  I dunno what the longest
   anim I done in c6pro - maybe 500 or 750 frames (OS X).

2. save the hiro.pz3 scene file that animated successfully in poser 7, then import it into c6pro.
   it may be necessary to read the manual to learn how to import a pz3 file, either using
   c6pro native importer or transposer.  it may be necessary to have an install of poser 6
   or poser 5 in order for transposer to work, unless they fixed that in c6pro 6.2.1 (I doubt it).