5.2-R Installation Issue

My apologies if this is the wrong list.

I've been having a long-standing issue installing 5.x onto a Dell PowerEdge
600SC. As far as I can tell, my issue specifically relates to PR 54549,
http://www.freebsd.org/cgi/query-pr.cgi?pr=54549.

5.0-R and 5.1-R always paniced booting the first time off of the CD-ROM.
5.2-R gets much further, but I still have some issues. The problem seems to
originate with the ATA controller, a ServerWorks CSB6 controller. I'm
getting the following kernel messages while booting the first time before
installation. Unfortunately the system doesn't respond to keystrokes
quickly, so these have been written down:

--
ata2-master: timeout sending command=ef
error issueing PIO command
error issuing ATA PACKET command
ata2-master: timeout sending command=a0
--

It simply doesn't seem to like the CD-ROM drive. It will get to the
installation menu, but it takes forever to respond to keystrokes after that.
There are about 30 timeout errors in total.

This is not an esoteric server, but I'm finding little information on how to
resolve this.

Additionally since I hopefully have a captive audience, could someone tell
me if I can safely ignore the following kernel message that relates to all
versions I've tried? 

--
pnpbios: Bad PnP BIOS data checksum
--

If anyone could shed some light on these problems, I would be indebted. I
need ACL support!

Paul