FreeBSD BETA5 & BETA6 won't boot

[Pratt, Benjamin E.]

I'm trying to install FreeBSD BETA #6 onto my computer but the burned ISO won't boot.  The boot is stalling just after detecting my CD-RW drive.  I'm not sure if it's with the CD-RW detecting or with mounting the root file system.  I also had the same problem when I CVSUPed my system from 5.2.1 to 5.3 BETA #5 along with the BETA #5 ISO.
 
I did not have a problem booting with 6.0-CURRENT as of a few days ago (it's what I'm running now).  I went to 6.0-CURRENT when Scot Hetzel suggested it may be an ATA driver in a post here: http://www.freebsd.org/cgi/getmsg.cgi?fetch=1432335+0+/usr/local/www/db/text/2004/freebsd-current/20040905.freebsd-current
 
I'm not sure if this is still an ATA driver issue with the 5.3 BETA releases but I'd really like to run 5.3 when it becomes stable.  I'd also like to wipe the drive and try a fresh install from ISO so what can I do?
 
Thanks for any help,
 
Ben