Memory exhaustion when installing kernel

[Cam]

Hi

While running 2.6.6-1.414 I tried to install kernel-2.6.6-1.422.i686.rpm
kernel-doc-2.6.6-1.422.noarch.rpm
kernel-sourcecode-2.6.6-1.422.noarch.rpm

(rpm -i kernel-*2.6.6-1.422*)

and got this error:

warning: /home/cxm/kernel-2.6.6-1.422.i686.rpm: V3 DSA signature: NOKEY, 
key ID 9d6b4012
memlock: Cannot allocate memory
Couldn't lock into memory, exiting.
mkinitrd failed

I have noticed that installing a new kernel rpm seemed like more and 
more work. This is on a 800MHz Pentium 3 laptop with MemTotal: 387132 kB

To try and fix the problem I removed and reinstalled the rpm, but got 
the same error.

Has anyone else seen problems like this? How can I recover from this?

-Cam