[CentOS] Server Crashing

Greetings.

Every couple of day's I have a web server running CentOS 4.1 with all
the patches as of Saturday  that is crashing every couple of day's.
Usualy between 4-6 am.
The Console shows:

Double Fault gdt at xxxx memory
Double Falut tss at xxxx memory

On reboot all is fine. 
It's running apache and DNS no SSH access. It passes memory test Memtest86.  

I can provide more information if you direct me on what to send.

Thanks
-Jay