Having a similar issue following screensaver (standard blank SS in windows xp) , my G5 right-click wont work coming back from screensaver; i've had it comeback intermitently, but havn't figured out what makes it work, besides full re-boot.
I have an IBM ThinkPad laptop and was having the exact same problem with my MX Laser Bluetooth mouse stopping responding after my laptop resumed from hibernation when using the onboard blue tooth adapter.
But I have now fixed the problem upgrading to the latest version of the Bluetooth drivers for my Laptop from IBM’s website.
I have this same problem with a new HP dv2000t and a V270. The Bluetooth drivers are the latest version offered by HP. It is really annoying to have to keep rebooting the computer to get the mouse to work. Help!