I don't think any USB devices would be causing the problem. It's hard to imagine that hub working well though. That's about 400mA over the limit, but then who knows the true current draw. Why fix it if it's working, right?
As far as the GPS, if it's working at 9600, keep it there. Sorry, I had assumed it was 4800 as that's the defaut for most GPS receivers. I'm not sure if it's worth messing with at this point. If it was working fine and now it's not, then there may not be anything you can do. I think you should focus on the BU-353 and see if you can get that working. Using XPort will help with hibernation.
The drivers for ACPI are on the Windows XP CD. Just insert the CD and right click on the one in Device Manager under Computer. If you have ACPI enabled, select "ACPI Uniprocesseor PC" or Multiprocessor, whatever you have.