I used to get that sometimes with Poser 5. Haven't gotten it at all with Poser 6 though.

Just click "OK", and see what your scene window shows up as. Then just set it to what you want again, and resave your preferences.

If I recall, sometimes the window was mini mini, and sometimes it was the same size, but way off the screen almost hidden behind the tool bar.

If that doesn't work, change your preferences to "factory settings", then close and reopen poser again.  Then set up the interface the way you want and resave your settings again.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi