won't boot off iso cd

[Anne Ramey <anner@xxxxxxxxx>]

I updated to 2.6.12 kernel without updating something else necessary, 
apparently and have hosed my system.  The real problem is that it won't 
boot of disk.  We had 2 64 bit systems have the kernel problem and the 
other is back up and running fine.  The only disk I can get the second 
system to boot is off a 386 iso, which causes problems when I try and do 
anything (including chroot /mnt/sysimage) so I can't really rescue the 
system.  I'd be ok with reinstalling, because I was just doing the 
initial system set-up anyway, but I can't figure out how to do that 
without being able to boot off a cd.  The instructions I've found from 
booting from the network start with--boot from an iso cd (not helpful). 
 Any input would be appreciated.

Thanks
Anne