MYSQL Error IN UserProfile (( err no.1))

[IRANCITY]

hi dear i have a problem in user profile
after i reboot my server i receive this err in user profile

Database error in vBulletin 3.8.7:

Invalid SQL:

SELECT user.*, (user.options & 512) AS invisible , avatar.avatarpath, NOT ISNULL(customavatar.userid) AS hascustom, customavatar.dateline AS avatardateline, customavatar.filedata_thumb, customavatar.height AS avheight, customavatar.width AS avwidth, customavatar.width_thumb AS avwidth_thumb, customavatar.height_thumb AS avheight_thumb

FROM userlist AS userlist
INNER JOIN user AS user ON (user.userid = userlist.relationid)
LEFT JOIN avatar AS avatar ON (avatar.avatarid = user.avatarid)
LEFT JOIN customavatar AS customavatar ON (customavatar.userid = user.userid)

WHERE userlist.userid = 2989
AND userlist.type = 'buddy'
AND userlist.friend = 'yes'

ORDER BY RAND()
LIMIT 0, 6;

MySQL Error : Can't create/write to file '/tmp/#sql_d1e_0.MYI' (Errcode: 13)
Error Number : 1
Request Date : Saturday, September 17th 2011 @ 11:02:57 AM
Error Date : Saturday, September 17th 2011 @ 11:02:57 AM
Script : http://forum.iecloob.com/member.php?u=2989
Referrer :
IP Address : 78.39.63.2
Username : Mr . Saeed
Classname : vB_Database
MySQL Version : 5.1.56

[kh99]

The server can't create a temporary file in the /tmp directory because of a permission error (maybe a mount failed?).

[IRANCITY]

how can i fix it ?