Can't seem to boot from 6.0-RELEASE

[Alex Mayfield]

I'm rather new to FreeBSD, and have been wanting to try it out.  However,  
I am unable to boot from either the i386 6.0-RELEASE bootonly or the i386  
6.0-RELEASE disc 1 CD.  I'm running an Athlon 64 3000+ on a WinFast  
755FXK8AA motherboard (Socket 939, SiS 755 North Bridge, SiS 964 South  
Bridge).  The boot CD dies right after ago0: figures out my SiS 755 with:

panic: pmap_mapdev: Couldn't alloc kernel virtual memory.

Having searched for my problem before posting, I found that another  
individual has had a similar problem to mine:

http://docs.freebsd.org/cgi/mid.cgi?20060122170123.I76421

I followed his initiative and tried the boot option that didn't use ACPI.   
No dice.  I also checked the MD5 of both CD's and they checked out fine.   
Finally, I tried to boot the amd64 version of FreeBSD, and this time it  
booted just fine and I got to an installation screen.  However, given the  
fact that there are no nvidia drivers for the 64 bit version, and certain  
programs being unavalable for amd64, I'd really just prefer to use the  
i386 version instead.

Thanks in advance for your help.

-Alex