That’s weird, that’s the first time I read such a issue.
I suggest you try the following :
– Disconnect Xkey
– Open audio/Midi utilities, MIDI devices window
– Select previous Xkey device(s) and delete it.
– Open disk utilities
– Repair disk permissions
– Re-connect Xkey
If you still observe the same issue, please try to connect your Xkey to a different computer.
Let me know if this helps.