[مشكلة] فى التحكم بالاعضاء database error

Database error in vBulletin 3.8.7:

Invalid SQL:
SHOW COLUMNS FROM user LIKE 'username';

MySQL Error   : Can't create/write to file '/tmp/#sql_3e18_0.MYI' (Errcode: 13)
Error Number  : 1
Request Date  : Wednesday, November 23rd 2011 @ 08:14:21 PM
Error Date    : Wednesday, November 23rd 2011 @ 08:14:21 PM
Script        : http://www.starsvb.com/xRMeR9e3/user.php?do=update
Referrer      : http://www.starsvb.com/xRMeR9e3/user.php?do=edit&u=5
IP Address    : 41.234.221.54
Username      : ÇĦĒĒŤÃĦ
Classname     : vB_Database
MySQL Version : 5.1.56-log