There's an easy way to import them manually without going through one at a time.  Find your LibraryPrefs.xml for the previous verison of Poser (say Poser 8), and copy it over to replace the  one for PoserPro 2010.  When you open PP2010, voila, your libraries are loaded.  The only extra step is to manually add the runtime for the previous Poser version (which can be done in Poser, of course).  And that's it.