Word, Excel, PPT, Entourage don't open

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)
Processor: Power PC

After installing Office08 and its updates, whenever I launch any Office
program (either from the dock, under the application folder, or by opening
an office document), the Microsoft Office Setup Assistant launches. From
there, I've tried re-runniing auto-update, registering, and everything
else. But after quitting the Setup Assistant, the program I tried opening
forgets to open. What's the problem? Could it be that I installed it from
a network account (w/ admin privileges?