To install it, I ran the installer until it fails (like the error you got). Then open device manager, and tell it to update the video card drivers. Tell it you have a disk, and point it to the ATI folder that the installer has left on the hard disk (can't remember where, but I imagine it's in c: ). Only problem is that there's 3 folders in the xp drivers folder - one is the drivers, one is the catalyst control centre, the other is the enhanced video support or something. But only the one with the drivers in will work 🙂
I had few crashes (just a couple when exiting certain 3d apps, none while just using windows or playing games). You can boot into safe mode, go to device manager, and tell the video card drivers to 'roll back' - that should fix it.