how to fix database error

[Kiran-E-Sehar]

Some times i face this error please help me and let me know how can i fix this error




Database error in vBulletin 4.1.2:

Invalid SQL:

SELECT userid,options,usergroupid,displaygroupid,lastacti vity,username
FROM user WHERE lastactivity > 1308268800 ORDER BY username;

MySQL Error : MySQL server has gone away
Error Number : 2006
Request Date : Thursday, June 16th 2011 @ 11:53:53 PM
Error Date : Thursday, June 16th 2011 @ 11:54:30 PM
Script : http://www.forum.kiran-e-sehar.com/
Referrer :
IP Address : **.**.**.**
Username : Admin
Classname : vB_Database
MySQL Version :


Thanks in advance