A month is nothing...the earliest post I've found on this is from 5/19/2003, entitled "USB mouse stops working with D600 and D/Port" -- so...make that nearly 11 months since it was first reported in the forums...probably longer since it's been reported to Dell.
not sure if you all are aware, but there is a workaround...you can run the USB ports as 1.1 instead of 2.0. I called Dell on this for my D/dock and that is what we did and it resolved the problem. I can sync up my IPAQ now with no problems. The only issue is when it notebook goes to sleep, it does not reconnect with the ipaq when it wakes up. However my usb mouse does just fine after the notebook wakes up.
if you look at other forum posts, you will find more information about this workaround.