db error: Incorrect information in '.../noticedismissed.frm'
 

One of my sites has suddenly sprouted the db error you see below. Nothing has been changed on the site for about a month, so it's a mystery why this happened today. Suggestions for a fix?
Code:
Invalid SQL:

SELECT noticeid
FROM noticedismissed AS noticedismissed
WHERE noticedismissed.userid = 2;

MySQL Error : Incorrect information in file: './username_forums/noticedismissed.frm'
Error Number : 1033
Request Date : Monday, February 15th 2010 @ 01:29:19 PM
Error Date : Monday, February 15th 2010 @ 01:29:19 PM
Script : http://sitename.com/forums/index.php
Referrer :
IP Address : 216.118.133.101
Username : myname
Classname : vb_database
MySQL Version : 5.0.89-community