Perhaps this may be helpful, if only to reassure some folks that this does appear resolvable.

I can confirm some of what has been reported and advised above.  A friend purchased P8 over the weekend and also encountered the absent library panel.  My own experience with Poser is limited so I was not able be of much help other than assisting in locating a solution. 

After two days of hair pulling and cursing what worked for him was an uninstal of Flash Player, a reinstall of both Flash for IE and Flash for other than IE.  This allowed the libary panel to appear, but not fully function.  A change to the settings in Zone Alarm, allowing Server access, freed the library panel to function fully.  It was not necessary to allow Internet Access in ZA.  

The only issue now is that CPU usage skyrockets whenever the Librabry panel is open.  This is being reported elsewhere and seems to be more of a Flash than Poser issue; although they've now been married for "better or worse."

His system is Win XP with Firefox as primary browser.  He seems happy with P8 on all other accounts so far.