I don't use poser library so never had this problem, I'm using library xl and with that one I can run 2 copies at the same time without a problem. I would suggest getting an external library for at least one of the poser versions to overcome this problem.

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