Live CD doesn't boot

I have been trying to boot the ubuntu 5.10 live CD to check for any issues before installing it, but I can't get it working properly.

My platform is a Compaq Presario V2000 series (V2433AU) notebook with the following:
    * AMD Turion 64 processor
    * ATI Radeon Xpress 200M display adaptor

Both the 32-bit and 64-bit PC versions fail during boot, but the 32-bit version gets a lot further into the boot process so I've focus on the 32-bit version here.

When the PC boots from the live CD everything goes well until it tries to start X windows (except that clock synchronization fails as expected without an internet connection when I do this offline). When it attempts to start X windows (right after failing clock synchronization) it gets as far as blanking the background of virtual terminal vt7 then exits with error.

The file /var/log/Xorg.0.log shows hundreds of error reports at this point. The following errors appear twice:
    drmOpenByBusid: drmOpenMinor returns -1023
    drmOpenDevice: node name is /dev/dri/card0
    drmOpenDevice: open result is -1, (Unknown error 999)
    drmOpenDevice: open result is -1, (Unknown error 999)
    drmOpenDevice: Open failed

Then "Unknown error 999" is replaced by "No such device" and repeats with "/dev/dri/card0" counting up to "/dev/dri/card254". Eventually this all ends with the following reprts/errors:
    (II) RADEON(0): [drm] drmOpenFailed
    (EE) RADEON(0): [dri] DRIScreenInit failed. Disabling DRI.
    ...
    Fatal server error:
    Caught signal 4. Server aborting

The problem appears to be related to the ATI Radeon adaptor as far as I can tell.