Proliant 5000 hangs on boot to 5.1 during install

[Rick Updegrove]

Hi,

I have a Compuke Proliant 5000 I would really like to use FreeBSD on

When I boot to CD or floppies using 5.1 I get all the way to:
"/stand/sysinstall running as init on vty0"
but the machine then locks up hard.

When I boot to CD or floppies using 4.8 I get nothing.  The machine 
won't boot to a 4.8 CD (that works in another machine)

Any ideas on what to try next?

TIA

Rick