MySQL Error : The table 'session' is full
 

So out of the blue my forum went down and has been displaying the following error:

Code:
Database error in vBulletin 3.6.7:

Invalid SQL:

INSERT IGNORE INTO session
(sessionhash, userid, host, idhash, lastactivity, location, styleid, languageid, loggedin, inforum, inthread, incalendar, badlocation, useragent, bypass, profileupdate)
VALUES
('a12668843dc093f385b3ff370dba7a73', 1, '208.63.102.196', 'b187d1cdde0e7bfb55ade89fc7a60622', 1263245218, '/', 0, 0, 1, 0, 0, 0, 0, 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.0.249.43 Safari/532.5', 0, 0);

MySQL Error : The table 'session' is full
Error Number : 1114
Date : Monday, January 11th 2010 @ 03:27:00 PM
Script : http://sunshineunderground.net/
Referrer :
IP Address : 208.63.102.196
Username : Bass Cadet
Classname : vB_Database

It's been a long time since I've modified the site in any way so I'm not sure how this just happened.

Anyhow, what's the fix? I've searched a bit here and elsewhere on the web and can't find a clear resolution.