postindex table DB errors

[محروم.كوم]

I am getting a lot of the following error.

Database error in vBulletin 3.8.5:

Invalid SQL:

SELECT postid
FROM vb3_postindex
WHERE wordid IN(871);

MySQL Error : Table './db_xlforum_2/vb3_postindex' is marked as crashed and last (automatic?) repair failed

Error Number : 144
Request Date : Sunday, June 6th 2010 @ 09:44:09 PM
Error Date : Sunday, June 6th 2010 @ 09:44:09 PM
Script : http://xlforum.net/vbportal/forums/s...php?do=process
Referrer : http://xlforum.net/vbportal/forums/search.php
IP Address : xxx.xxx.xxx.xxx
Username : xxxxxxxxxxx
Classname : vB_Database_MySQLi
MySQL Version :

Also the post index table shows Data Length of 0 and an Index Length of 0

When I run Repair/Optimize I only get this: Table './db_xlforum_2/vb3_postindex' is marked as crashed and last (automatic?) repair failed

Anyway to fix this?? __DEFINE_LIKE_SHARE__