Well, not one I've run into before, but off the top of my head I'd say your best bet would be to go under the Edit menu and select general preferences (I think ctrl K is the hotkey for it).

Under the interface tab, select "launch to factory state", then close Poser and restart it.  If this is some sort of setting in poser causing the problem that should do the trick, and if not at least it will tell you that it's not a Poser setting that was changed that is causing the problem.

Stepdad