booting problems with the cdrom

[scalopus]

Hi all,
  i am trying to install dfbsd in a IBM Netfinity 5000 server:
http://www-1.ibm.com/support/docview.wss?uid=psg1MIGR-49JP55, 
but I have several problems with the cdrom.

1) First i tryed the 1.2 release, this iso:
2CSNAP-20050731-1130-Release-1.2.iso.bz2
  The cd even doesn't boot, i can't see the Boot Menu (the
dragonfly acsi), it freezes in the "BTX Loader". 

2) Later i tryed the development iso:
2CSNAP-20050724-2330-Devel.iso.bz2
  This cd boots, i can see the Boot menu, but when booting
the kernel it crashes when accessing to the ata, suppose the
atapi, the acd0 cdrom, with the following error:

acd0: MODE_SENSE_BIG command timeout - resetting
ata0: WARNING: atapi resetting donecount 28 for retry
ata0: resetting devices .. done

  It repeats about 5-7 times, and after it kernel crashes:

Fatal trap 12: page fault while in kernel mode
fault virtual address = 0x20029
fault code = supervisor read, page not present
instruction pointer = 0x8:0xc01a0c51
stack pointer = 0x10:0xc0715ca8
frame pointer = 0x10:0xc715ccc
code segment = base 0x0, limit 0xffff, type 0x1b
	     = DPL 0, pres 1, def32 1, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 0 (swapper)
current thread = pri 108 (CRIT)

kernel: type 12 trap, code=0
Stopped at acd_describe+0x7c0: movzbl 0x5(%eax),%eax
db>

  Maybe it is DMA issue, the CD-Rom in the bios is in
PIO Mode 3, and i can't change it.
  I can install fbsd (but i dont see after installation
the cdrom), windows 2000 server and nbsd loads the
installation. So the cdrom works fine.

  I have installed dfbsd in a PII-233MMX clone and in a
portage 3490CT laptop without any problem, but now i 
dont know what to do. I have probed all the boot 
possibilities, without acpi, single-user, safe-mode, 
etc. always same error.
  Are there any boot option to set off the dma? 
  Isn't there any way to stop waiting for the cdrom? 
3 retrys and after failure follow to load the kernel, 
for example.

Thanks for your attention.
Regards,
  scalopus