I have a similar problem myself. I have 3 VA11A's in all, and they all work just great on 2 computers Running XP Pro, but have a problem with the computer running XP Home edition. Strange as it may seem, if I disconnect the VA11A from the XP Home computer while it is running, then plug it right back in, it's detected with no problem and everything works great after that. But, once I shut down the computer at night, and turn it back on in the morning, it seems to lose the VA11A and Windows Found New Hardware wizard pops back up, and as usual doesn't find the correct driver. Yet, as I said above, if I disconnect it and plug it right back in, it does.
It's not the hardware, because it does the same thing with any of the 3 VA11A's I have, yet they all work just great on the other 2 computers running XP Pro whether I shut them down over night, or anything. This leads me to believe it's either XP Home, or something else on the XP Home computer itself causing the problem. To add to the frustration, this problem never occurred before even on the XP Home computer until after it was formatted and reinstalled.
I suggest you try the same thing, unplug the VA11A while the computer is turned on and then plug it right back in and see what happens.