I have also noticed that Crap Cleaner now spends considerable time clearing IE5* and XML files, if -and only if- I have had P8 open;  I wonder if this is another manifestation of the memory leak I have noticed.  Open Task Manager.  Open P8.  Don't do anything with Poser 8, just watch Task Manager and note the ever-climbing memory allocation P8 is using.  It would be a serious issue for trying to render out 1200 frames of animation.

*Even my older machines have IE8, and I don't use it;  I browse with FireFox.  I have both XP and Vista machines;  both show this behavior.  Like the OP, I also have dual Poser installations on each machine - Poser 7 & Poser 8 on the 32bit machines, Poser Pro & Poser 8 on the 64bit machines.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5