error installing FreeBSD 5.1

[Andrew]

Hello

I have been trying to install FreeBSD 5.1 from DVD-rom and i can boot 
the system from the dvd OK set up my parftitions and all but when it 
comes to commit at the end i get a error message.

I have been following the examples in book
(The Complete FreeBSD)
O'Reilly
Greg Lehey


Every thing runns OK untill this stage even booting from the dvd-rom

error mounting /dev/acd0 on /dist: Input/Output error (5)


Configration is

MSI K7T Turbo
2x512Mb sdram
XP2400
Matrox G400 video card

Pioneer DVD-rom    Primary master Motherboard
LG burner   Secondary master Motherboard

Promise Primary master    80Gb western digital
Promise  Secondary master    80Gb western digital