I'm on XP, problem also there. It doesn't matter where I install it, problem appears. I've tried various firewalls and anti-virus apps, but doesn't make a difference.

I still haven't figured out what causes it, I stopped doing that and looked for a work around, for me problem is gone.

Artwork and 3DToons items, create the perfect place for you toon and other figures!

http://www.renderosity.com/mod/bcs/index.php?vendor=23722

Due to the childish TOS changes, I'm not allowed to link to my other products outside of Rendo anymore :(

Food for thought.....
https://www.youtube.com/watch?v=pYZw0dfLmLk