LinuxQuestions.org - XP Pro NTFS and Red Hat Boot with Grub on Seperate Drives

I've updated my friend's kernel to 2.6.5. 2.6.x doesn't allow boot disks, which was how he booted before. Windows XP Pro is on the first hard drive and uses NTFS. Red Had 9 is on the second hard drive. I've installed Grub on the MBR of /dev/hda, but whenever it boots, it shows error code 21, on stage 1.5, meaning "unknown boot error".
fdisk -l:
Disk /dev/hda: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 4865 39078081 7 HPFS/NTFS

Disk /dev/hdb: 81.9 GB, 81964302336 bytes
255 heads, 63 sectors/track, 9964 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hdb1 1 4177 33551721 c Win95 FAT32 (LBA)
/dev/hdb2 * 4178 4190 104422+ 83 Linux
/dev/hdb3 4191 9899 45857542+ 83 Linux
/dev/hdb4 9900 9964 522112+ f Win95 Ext'd (LBA)
/dev/hdb5 9900 9964 522081 82 Linux swap

The Grub config file:
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd1,1)
# kernel /vmlinuz-version ro root=/dev/hdb3
# initrd /initrd-version.img
#boot=/dev/hda
default=1
timeout=10
splashimage=(hdb3,1)/grub/splash.xpm.gz
title Red Hat Linux (2.6.5)
root(hdb3,1)
kernel /bzImage ro root=LABEL=/ hdd=ide-scsi
title Red Hat Linux (2.4.20-6smp)
root (hdb3,1)
kernel /vmlinuz-2.4.20-6smp ro root=LABEL=/ hdd=ide-scsi
initrd /initrd-2.4.20-6smp.img
title DOS
rootnoverify (hd0,0)
chainloader +1

Thanks in advance.