PMJI: Some (very) basic questions:
1. Do other USB devices connect OK?
2. Does the device show up in VM/Removable devices (or the status bar) when you plug it in?
3. In VM Settings, is the "Automatically connect new USB devices" checked?
4. Is the USB compatibility setting correct (are you using USB 3.0 or 2.0?)
5. Have you rebooted the host and guest?
Lou