Just out of curiousity, what kind of handles does ProcessExplorer show as being open? Are a lot of them file handles? If you run SysInternals FileMon when starting Poser, you can see it hittling all the files in your runtime as it populates the library. I wonder if it's keeping all of those open.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken