Msg 'Sorry cannot complete..Constraint violation'

CiviCRM installation worked fine, on 02/23/14, got the error msg re constraint violation when attempting to view Event Info, no mods/rows added to the database, no deletes... Unfortunately I didn't have Debug turned on. I dumped/copied the current CiviCRM database, restored from a backup and was able to view Event Info. Then I did a comparison of the 2 databases (the one I exported and the one I restored from) using an ascii file compare program (CompareIt) - only cache data and acl_cache data appeared to be different. No data in civicrm_event differed, or other tables than cache.
Later, I imported the 'bad' database back into a new database for testing, turned on debug in CiviCRM, connected to this new 'test' database ..no error, no 'constraint violation'...
Is it possible that this issue was due to MySQL locks not being released in a timely fashion? I don't know how one could easily duplicate this problem now! It is seemingly not due to persisted data in the DB..