In one case, this problem was solved by identifying the user's PCR-300 as a generic keyboard in the MIDI Tab of the Preferences window in Reason, rather than as a "PCR series" Edirol keyboard. We found that when the keyboard was identified as an Edirol PCR Series in Reason, it caused problems in CoreMIDI that carried over into Live after Reason was shut down.

Also, it is always a good idea to check the manufacturer's website for driver downloads/updates, as these kinds of issues are usually driver-related and are most commonly solved by an update (which was not available in this case).