"Task" - Menu in PWA does not open (Project Server 2003)

[Flinte]

Hello everybody,
we have just Installed a Project Server 2003. After a couple of
problems, the system now runs and everything works, except of the
"Tasks" Menu.

Problem:
When you open Project Web Access and click on the "Tasks" Button, the
Tasks page appears, and after one second the Browser jumps back to the
"Home" page.

I tried it with different users, and also with Users that have all
Rights and a lot of assigned tasks.

Did someone else encounter this Problem?

Greetings,
Michael


System:
- Project Server 2003, running on an virtual machine
- Service Pack 2a + Post Servicepack 2a hotfix
- SQl Server 2005 and Analysis Services 2005 - on an other virtual
machine
- OLAP Cube is working
(yes, the installation was an adventure...and took a lot of time)