I received this lovely little error message towards the end of my JDK 1.5.0_03 install on my XP Pro at work:
I didn't have any browser running at the time. It turns out that Google Desktop was chewing on some freshly installed files that the JDK install process was trying to then patch. At least that's what I think is happening (and I might be wrong.)
Telling Google Desktop to "pause indexing" fixed the situation.