I've encountered similar errors on a certain desktop that I thought to be as compatible as a pc could be. The same install/live-cd disc of Kubuntu 6.10 worked flawlessly on a few other computers, but this certain pc just refused to boot, or if it booted it crashed occasionally, froze and what's more important, when I tried to install the system (I know it only takes something like 15 mins) to see if it worked better from the harddisk, the installation never accomplished successfully.
After quite a lot of tries I ended up with the conclusion that some part of the hardware didn't work with this distribution, and as I didn't have much time to investigate it, I just left it uninstalled.
My advices are, unless you figure out something more clever, to try the alternate install disc and see if the harddisk-installed version works better; the alternate disc has some benefits in the installation compared to the regular one (more options, mainly), so you might be able to install that. If it fails, try some other distribution.
As a sidenote, I tried Knoppix live-cd with the very same pc and it worked flawlessly. Kernel versions weren't exactly the same, so it might be that. Or something else.