This has never happened to me before. Can anyone tell me what might be
the problem?

When playing a midi file it just stopped as if paused (but it wasn't)
and after a little wait crashed back on again in a clashing of notes
that continued a bit or just abruptly ended. This happened a couple
more times and I was panicking. I noticed when one continued on that
the syncing of the beats was off to the melody that was still playing
when in started up again.
Then it was fine for awhile then it happened again and it brought up a
msg saying I/O Error

Do you have any idea what could have happened? It then didn't give me
any more trouble for the night.

I'm scared to death it's going to do this on a regular basis. With all
the gigs I have it'd be an absolute disaster. If you think you know
what it is and how it could be fixed, please let me know.