Does it have a device number in LinuxMCE? If so, it would be helpful to post a snippet of the follow logs
"tail -f /var/log/pluto/<device id and name>.log" or if the admin has it available, just cut and paste if from there.
The reason I mention this is that I've been having problems with my usb-to-serial cable as well and this seemed to give me something to start with at least.