Installation problem with 5.1

[Service Commercial]

Hi,

I use since 4.8 since many weeks now on my smp system :
tyan tiger mpx + 2 AMD MP 1800 + 756 Mo ECC
3ware 7000 + 2 X 40GO Udam 100 7200t seagate
ati rage pro 128 16mo agp 2x
cd-Rom plextor 54x on ide1
floppy on a and that's all !!!
com1, com2, mouse, and parallel port are disabled in the bios

Since i begin to boot on the 5.1 installation CD with any option the system hangs on "lockmgr" and prompt to reboot at any time.

Any idea ?

Regards,

Loïc Fraison