Seems like every time I try to use the Xadow board, I have to spend hours getting it to program via the Arduino IDE. This time, the solution seems to have been putting this in a file called /etc/udev/rules.d/78-xadow.rules and then rebooting:
ATTR{idVendor}=="2886", ENV{ID_MM_DEVICE_IGNORE}="1"
ATTR{idVendor}=="2886", ENV{ID_MM_DEVICE_IGNORE}="1"