Trying to install from CD on Sun Netra. Getting Illegal Instruction error after "Loading initial ramdisk"

Trying to install Ubuntu Server 6.06 LTS on a Sun Netra t1 (UltraSPARC-IIi 440MHz). I made the install CD and tried to boot from CD. Here is the log:

Netra t1 (UltraSPARC-IIi 440MHz), No Keyboard
OpenBoot 3.10.27 ME, 512 MB memory installed, Serial #16348474.
Ethernet address 8:0:20:f9:75:3a, Host ID: 80f9753a.

Executing last command: boot cdrom
Boot device: /pci@1f,0/pci@1/pci@1/ide@e/cdrom@2:f File and args:
SILO Version 1.4.10
\

                       Welcome to Ubuntu dapper!

This is an Ubuntu installation CDROM, built on 20060811.1.
Keep it once you have installed your system, as you can boot from it
to repair the system on your hard disk if that ever becomes necessary.

WARNING: You should completely back up all of your hard disks before
  proceeding. The installation procedure can completely and irreversibly
  erase them! If you haven't made backups yet, remove the rescue CD from
  the drive and press L1-A to get back to the OpenBoot prompt.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

[ ENTER - Boot install ] [ Type "rescue" - Boot into rescue mode ]
boot:
Allocated 8 Megs of memory at 0x40000000 for kernel
Loaded kernel version 2.6.15
Loading initial ramdisk (4861231 bytes at 0x20000000 phys, 0x40C00000 virt)...
Illegal Instruction
ok