مشكلة Database error

Database error in vBulletin 3.8.1: 
 
Invalid SQL: 
 
    SELECT COUNT(*) AS count 
    FROM attachment AS attachment 
    INNER JOIN post AS post USING (postid) 
    WHERE attachment.visible = 0; 
 
MySQL Error   : Table './القاعدة/post' is marked as crashed and last (automatic?) repair failed 
Error Number  : 144 
Request Date  : Tuesday, March 31st 2009 @ 08:36:50 AM 
Error Date    : Tuesday, March 31st 2009 @ 08:36:51 AM 
Script        : http://www.bntsouria.com/vb/admincp/index.php?do=home 
Referrer      : http://www.bntsouria.com/vb/admincp/ 
IP Address    : ..... 
Username      : ..... 
Classname     : vB_Database 
MySQL Version : 5.0.67-community-log

Database error in vBulletin 3.8.1: 
 
Invalid SQL: 
 
            SELECT MIN(postid) AS postid 
            FROM post 
            WHERE threadid = 4585 
                AND visible = 1 
                AND dateline > 1238374764 
 
            LIMIT 1; 
 
MySQL Error   : Table './القاعدة/post' is marked as crashed and last (automatic?) repair failed 
Error Number  : 144 
Request Date  : Tuesday, March 31st 2009 @ 08:42:26 AM 
Error Date    : Tuesday, March 31st 2009 @ 08:42:26 AM 
Script        : http://www.bntsouria.com/vb/showthread.php?goto=newpost&t=4585 
Referrer      : http://www.bntsouria.com/vb/ 
IP Address    : ........ 
Username      : ........ 
Classname     : vB_Database 
MySQL Version : 5.0.67-community-log