Could you please provide us with some additional details?
- What OS is installed on the server and client machines?
- What is the make and the model of the shared USB device?
Also, please provide a small memory dump that was generated as a result of the crash. Those are usually created on every BSOD occurrence.
To find out where minidumps are stored on your system, right-click "My Computer" -> "Properties" -> "Advanced" -> under "Setup and Recovery" click "Settings" and check the "Write debugging information" section for the path to "Small memory dump" files.