I'm on an iMac, 10.6.3 .
Tried to see if I could replicate your problem  however it does work as it should on my set-up.

In the meantime, until someone comes along who can be more helpful:
if you look in
Applications>PoserPro2010>runtime>Python>PoserScripts>Projects  
the hmtl files for what you should be seeing in that window are there. (And if they aren't there that will be one reason why they won't open.)
If you click on them they'll open in your browser and at least you can read the info in them that way.

3 things I'd try myself:

-A full re-install of Poser just to see if that does the trick with a full system restart after.

-consider updating Python on your machine.
Info here: http://python.org/download/
Apparently Leopard has 2.5 installed but perhaps updating to 2.6.5 will do the trick.
(I just checked and I have 2.6.4 on my machine)
Maybe ask about this in the Mac forum here for more info on updating it.

-Definitely submit a bug ticket with SmithMicro to report this problem if it persists.

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python