It does not appear to be a heat issue; temp monitor and iStat both show that the CPU temp almost never goes above 130 degrees F. The internal red LED's don't always come on after a KP but when they do it's 1 or 2 as I recall. The only info I have about that from Apple docs says "Contact a service provider".

I talked to the service dept at the local Apple reseller and was told that KP's can be caused by HD problems, OS problems, etc. I've loaded a fresh copy of 10.4.11 on a different HD and will run from that and see what happens.