Installed Portal Add ON / FORUM / Systemadministration - Navigation Cache?!

Hi,

i installed the Add ON FORUM for our Portal.

I ve restarted the whole Portal after that.. now the Menupoint:

Navigation Cache under System Administration - Detailed Navigation is gone?

I only see there: Short URLs... before i installed the FORUM Component there was over "Short URLs" The Point:

Navigation Cache...?!

Did anybody knows whats happened there? How can i clear now the Navigation cache?

Please help.

regards

Bjoern