FC3: KDE Applications menu is empty

[sz beam]

On one of the 2 machines I upgraded from FC2->FC3, the KDE "K" menu 
shows just "No Entries" nothing under "All Applications". And when I 
try to open any file in Konq, or open an attachment with KMail, the 
"Open With..." dialog comes up but there is nothing in the "Known 
Applications" box.

So in short, KDE seems to be unable to find any applications at all for 
the menus. 

Oh and, on this machine, under FC2, I'd upgraded KDE using the packages 
from http://kde-redhat.sf.net/ to kdebase-3.2.3-2.0.1.kde, etc. - the 
other one, which works fine, had the default Fedora updates package, 
whatever that was.

So any ideas? How does KDE populate the Application menu? would love to 
know where to start looking,

thanks