Forum Persistent Database Cache Error
 

For the best part of a month now I've been experiencing some strange issues. Periodically my site has been going down and it's consistently been to do with the cache - sometimes a few days a week.

Every time we get this message, which floods our inbox with dozens of emails...

{
Database error in vBulletin 4.0.5:
Invalid SQL:
UPDATE cache
SET locktime = 1359949414
WHERE cacheid = 'vbcms_item_1_data';

MySQL Error : UPDATE command denied to user '[omitted]' for table 'cache'
Error Number : 1142
Request Date : Monday, February 4th 2013 @ 03:43:34 AM
Error Date : Monday, February 4th 2013 @ 03:43:35 AM
Script : http://www.sg-virtualseries.com/forums/content.php
Referrer :
IP Address : 81.135.10.74
Username : Hyncharas
Classname : vB_Database
MySQL Version : 5.0.92-50-log
}

I haven't updated my build since I purchased a license, so is this a server problem or something else? How do I solve it?