I had a similar problem with my T40. I downloaded the software from IBM at
http://www-306.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-50245, but it didn't seem to work. So I removed the IBM software to use the built-in MS software (with WinXP). To add a device, hit Control Panel, Wireless Link, and the Bluetooth tab.
When I did install the IBM software, I got the icon in the System Tray, but it was saying that it couldn't find the device. Now, with the built-in Windows software, I don't get a System Tray icon, but things work.
Anyway, I found the built-in Windows Help and the Access IBM help to be useful.
Good luck!