Boot from thumb drive: "Ran out of input data"

[Chris St. Pierre]

I'm trying to boot the RHEL4u5 installer from a thumb drive on an HP
DL145g3.  When it boots up, I get :

Could not find kernel image: linux

At the boot prompt, I entered "vmlinuz initrd=initrd.img"; it loads
the kernel and initrd image, but then dies with "ran out of input
data."

I've checksummed the ISOs I downloaded, tried two USB drives, and both
front USB ports on the machine.

To put the boot image on the thumb drive, I did:

dd if=diskboot.img of=/dev/sdb

I was able to boot the RHEL5 installer from a thumb drive on
this machine without a problem.

Any ideas?

Chris St. Pierre
Unix Systems Administrator
Nebraska Wesleyan University