Very interesting. I still think it is very possible that you have a flaky drive or maybe a bad cable and the reason you are seeing this is not because of ext3, but because of the newer kernel being more sensitive to a hardware issue. But of course I could be completely wrong If you are up for a little testing try this kernel which is patched up to 2.2.17 but does not contain ext3 support or hijack. Might help us narrow down the problem a little at least.

-Mike