MySQL server has gone away

[محروم.كوم]

I get these errors sometimes, this started after I moved my website to a new ISP.
This ISP uses seperate MySQL server, so not the "defualt" al local database server.

It works well, but in some occasions I get these:

------------
Database error in vBulletin 3.8.3:

Invalid SQL:

UPDATE session
SET lastactivity = 1250104591, location = '/forum/local_links.php?action=jump&catid=6&id=102'
WHERE sessionhash = '27ff755e247be3c9f02c8ddf786b5c4a';

MySQL Error : MySQL server has gone away
Error Number : 2006
Request Date : Wednesday, August 12th 2009 @ 09:16:31 PM
Error Date : Wednesday, August 12th 2009 @ 0911 PM
Script : http://www.pieppiep.nl/forum/local_l...catid=6&id=102
Referrer : http://www.pieppiep.nl/forum/local_links.php?catid=6

IP Address : 94.209.8.185
Username : Niet geregistreerd
Classname : vB_Database
MySQL Version :
---------

I get them on different pages, and from diferent users, registered and not registered.

The pages work fine when I test them later...

My ISP has no logs or records about theyre MYSQL server beeing down/and or any complains from other customers.

Any ideas anyone? __DEFINE_LIKE_SHARE__