Originally Posted by antik
I think this is DMA problem with your cdrom drive. PC-BSD got DMA enabled by default.
I remember having a DMA problem on a Compq desktop PC. The installation booted up ok but then it kernel-dumped just after the introductory screen with the selection numbers (1. Boot FreeBSD 2. Boot with ACPI disabled etc...)
I went into BIOS and disabled IDE DMA transfers. The installation went smoothly after that, with ACPI enabled.
What bugs me most is that you say you have installed FreeBSD 6.1 on that machine and current PCBSD 1.1 has the same OS under the hood.
Maybe it's time to try a new cdrom-drive. How old is the machine / cdrom drive anyway?