I was reading bits and pieces and some of this sounds like an apache bug. The posts I read were more targetted towards Apache and Macs, but the unlying problem has something to do with Apache detecting polling for the sending of data and having it incorrectly report a finished download. The other posts I read suggested reverting to older version of apache, or going through and manually patching/building. On xp though, this would be a pain. I'd suggest sticking with the 2.0 apache rather than try to jump to 2.2. I know that the latest/greatest is not always the most stable with some of the open source software. (see also Tomcat).
I'll have to track down and see if I can find the bug there were referencing and see if it matches this version of apache too.