I need help with Vbulliten mail system error

[Nickbe]

I keep getting this error when I try to send mail to my forum members I am sending about 1300 emails I sent some earlier and about 1100 of them bounced back to me. I have just tried sending to only 50 people at a time and I have only got the error once as opposed to 13 times when i was sending 100 at a time.

Any ideas?

Database error in vBulletin 3.6.1:

Invalid SQL:

UPDATE session
SET lastactivity = 1186657673, inforum = 0, inthread = 0, incalendar = 0, badlocation = 0
WHERE sessionhash = '2a2588ff5fcd9d4896dad7c695d1df29';

MySQL Error : Lost connection to MySQL server during query
Error Number : 2013
Date : Thursday, August 9th 2007 @ 07:08:14 AM
Script : http://www.forexclarity.com/forum/ad...?do=dosendmail
Referrer : http://www.forexclarity.com/forum/ad...?do=dosendmail

Username : Nick
Classname : vb_database