Adding to sveakul's suggestion for things to try, a google search on the error message usually seems to point towards some database issue.
Maybe corrupted, maybe lack of disc-space, not sure.
You could see if you can revert to a backup version of MusicBee's database file, or rebuild it somehow?
I have no experience or actual knowledge on how to do such things, but a forum search is likely to give you some pointers on that.