I had a good look around, as I am having major XP Pro issues as well, but none of the info I found related to your error message.

If anyone knows any info which can help me I'd be very grateful too - the background:

started getting blue screens and hangs, sometimes with the IRQ_IS_LESS_THAN type errors. General advice on internet seemed to be wipe page file and rebuild it.

This worked, but on next reboot the machine hung on BAD_POOL error, and now even if I boot using a genuine XP CD it hangs. It will not let me get to the recovery console.

It appears to be hanging on mup.sys, and some advice appears to be "try removing cards one at a time" so that's what I'll be doing tonight, but if anyone has any insight please let me know:-)

It is an Athlon, with ATI 9600, Audigy Platinum, mostly bog standard.