I've noticed that some other people mentioned that they couldn't install the new kernel thru up2date... I'm also experiencing this problem.  If I try to use up2date, it tells me that it has an invalid GPG signature, and the file was corrupted.  I've also tried downloading the rpm manually, and using the rpm commandline to install it.  When I try that, it complains:
error: kernel-2.4.22-1.2129.nptl.i686.rpm: V3 DSA signature: BAD, key ID 4f2a6fd2
error: kernel-2.4.22-1.2129.nptl.i686.rpm cannot be installed
thx!
 
k