I've found that I had to close Poser before importing a figure to Vue. Annoying, but liveable. After the import, I can open Poser back up without any problems. I think it may be a Windows thing. Vue may be making a call to Poser, and is being blocked by Windows since the program is already in use. It's like trying to open a file with a program that is already in use by another program. Sometimes it works, sometimes it doesn;t.