To nip the upcoming rumor in the bud:
Poser 7 will EASILY open Poser 4, Poser 5, and Poser 6 scenes without any issues whatsoever. I personally have now opened over 30 scene files that I made in Poser 4 and Poser 6 and every single one of them opened fine and rendered exactly the same as if I opened them in Poser 6. It would be incredibly foolish if e-frontier didn't allow Poser 7 to open pre-existing Poser scene files.
 
Call me dense, but I still don't get why you would "File > Import" an existing Poser scene instead of just going to "File > Open". Do you normally import your pre-existing Word documents into Word 2000?
 
If you want faster renders, go to Edit > General Preferences, click on the Render tab, set the "threads" slider to 4, and click the checkbox underneath. This will allow the FireFly renderer to use multiple processors (if you have them) and separate memory threads.

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