Intellimouse Issue

Thanks in advance to anyone who can offer any advice. Here is my issue:

I've been using a Microsoft Intellimouse (Microsoft 5-Button Mouse with IntelliEye, ver. 3.0) for over a year now and never had any issues with it. Since upgrading to Leopard, I have problems dragging and dropping items on my desktop.

Basically I can highlight a file and drag it, but when I go to drop it, it remains 'stuck' to the mouse pointer. I can't click on anything else once this happens, and the only way I've been able to stop the problem is to unplug the mouse from the USB port. Plugging the mouse back in either 'unsticks' the selected file or causes a gray warning screen to appear telling me to restart my Mac immediately.

I've tried it my mouse on different USB ports - all have the same issue. I upgraded the mouse's driver (to 6.2.2) and still have the same issue. Also zapped my PRAM and repaired permissions - none of which helped. I've switched back to the mouse my Mac came with, and while mouse has no problems, it is VERY difficult to control.

Any suggestions/advice would be greatly appreciated.