Might be stupid questions but they will help trouble shoot:
1) The first time you plugged it in, did a yellow box appear in the lower right corner indicating it recognized the new USB device?
2) Does your PC beep or acknowledge the USB cable being plugged in now?
3) Do you have any other USB devices plugged in? (unplug them)
4) Have you tried disabling every start-up item that can obviously be shut off while you do this? Don't do a safe boot because I think it affects the way the USB functions.
5) Do you wait a minute or so after you start the Desktop manager before plugging in the Curve?
6) Is your Curve on and settled before you plug in?
7) Have you tried completely removing the Desktop Manager and reinstalling it?
8) Have you tried a different USB cable?
9) Do other USB devices operate normally through the same port?
That's all I got.