Probably they stuck stuff in there that they replaced, and now they want to restore it.
Install routines largely blow, and that's an understatement. I think it must be where the worst developers in a shrinkwrap software company end up working. The other day I tried to uninstall Norton from a laptop my daughter received for graduation (along with a zillion other pieces of junk HP put on it). Everything but the LiveUpdate part uninstalled without incident. LiveUpdate's uninstall kept puking, and despite lots of research I couldn't find a way to fix it. When I went in to do a manual removal I found more than 100 registry keys that had to be deleted. Including all the keys that reference the virtual device drivers Norton uses to hook various low level system APIs. Yeah, LiveUpdate really needs those to connect to the net and download packages. It took me more than an hour to fix.
Install/Uninstall software on Windows (anyway) sucks. Or rather I should say the implementations of the scripts suck. Maybe the script engines suck too. Or maybe its just the developers who suck. Anyway, it's an area that needs a lot of improvement, and as a developer myself I can't figure out wtf is so hard about uninstalling an application. Undo what you did and get the hell out. If you replaced system files with different versions and are now caught in a bind because the original original should not be the original anymore, that's just crappy design.