No entry sign on first boot - Root device not found?

Dell Dimension 5150
P4-HT 3.0GHz
3GB
ATI Radeon X300 128MB

Installed iDeneb v1.3 with just speedstep kernel and graphics drivers. Upon first boot after a minute of normal loading a no entry sign appeared over the apple logo. Restarted with -v and each minute or so the screen reports something about searching/not finding a 'Root Device'

Searching the web points towards SATA drivers need adding to the install, but I can't find anything related to them in the customizations. Anyone know what customizations I need to make?

Cheers

Thom...

What distro did you use and how did you customize your installation? btw try to disable your HT Feature from the BIOS, check if you have AHCI SATA Support and try to Enable it, good luck