Database Error .... any one can help ?!

when iam going to send mail to members

i got this error

Database error in vBulletin 3.6.7:

Invalid SQL:

                    UPDATE session
                    SET lastactivity = 1181325219, inforum = 0, inthread = 0, incalendar = 0, badlocation = 0
                    WHERE sessionhash = 'fa7352844d0348f30261b251a15b79b6';

MySQL Error  : MySQL server has gone away
Error Number : 2006
Date         : Friday, June 8th 2007 @ 08:55:18 PM
Script       : /vb/admincp/email.php?do=dosendmail
Referrer     : /vb/admincp/email.php?do=dosendmail
IP Address   : 00.00.000.000
Username     : Admin
Classname    : vb_database

and it apper again today

Invalid SQL:

                    UPDATE session
                    SET lastactivity = 1181646675, inforum = 0, inthread = 0, incalendar = 0, badlocation = 0
                    WHERE sessionhash = 'fde494011f1858a5c3d6fffb39ceb769';

MySQL Error  : MySQL server has gone away
Error Number : 2006
Date         : Tuesday, June 12th 2007 @ 02:15:22 PM
Script       : /vb/admincp/email.php?do=dosendmail
Referrer     : /vb/admincp/email.php?do=start
IP Address   : 00.00.000.000
Username     : Admin
Classname    : vb_database

Some Info :- i convert this forum form VB to IPB and convert it again from IPB to VB again and when iam going to Update Counters >> Rebuild Post Cache
i got Errore ?

Any idea to help ??!!

[Muellmann]

Check out your mysql version and maybe the link below helps you as well:
B.1.2.8. MySQL server has gone away
If the script runs to long it can come this error as well.

You can change the time limit by setting the wait_timeout variable when you start mysqld

[UltimateOreo!]

If your "renting" a server from someone, /shared hosting, ask them about the mysql. If it got uninstalled, it is not running ect.....

[Mudvayne]

Hello,

This is a MySQL issue, here are a few of the reasons for the MySQL server going away:
http://www.vbulletin.com/forum/showt...265#post310265

Also from the MySQL site:
http://dev.mysql.com/doc/refman/5.0/en/gone-away.html

You should contact your host and have them investigate this for you.