DISASTROUS mysql errors

[carwash]

Every time an action is performed on my board, this shows up:

Database error in vBulletin 3.5.0:

Invalid SQL:

REPLACE INTO vb_postindex
(wordid, postid, score, intitle)
VALUES
(337, 142685, 1, 1), (1705, 142685, 1, 1), (194, 142685, 1, 0);

MySQL Error : Can't open file: 'vb_postindex.MYI'. (errno: 145)
Error Number : 1016
Date : Monday, May 1st 2006 @ 06:10:22 PM
Script : http://www.talksox.com/forum/newreply.php
Referrer : http://www.talksox.com/forum/showthread.php?p=142676
IP Address : REMOVED
Username : REMOVED
Classname : vb_database

The post is then made like 3 times, take a look around the board and you can see. What is causing this, as it is severely hampering usage.

Thanks.

The problem seems to be that the vb_postindex table is EMPTY. I hope to god that this should be the case, or else I'm in some serious trouble here.