Invalid SQL

[winky8300]

hello everyone

month my site after my hoster my forum receives sql injections have the down site.
deuis yesterday I received in my mail database error from the same IP, can someone explain to me please.

Database error in vBulletin 4.2.1:

Invalid SQL:

REPLACE INTO guest
(guestid, useragent, lastactive, spider, script, rdata, ipaddress, altip)
VALUES
('5b608da55a806e31069c1c92443f8ef6', 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.66 Safari/537.36', 1378972234, '', 'login', 'a:14:{s:2:\"do\";s:5:\"login\";s:17:\"vb_login_username\";s:10:\"paladin_75\";s:17:\"vb_login_password\";s:0:\"\";s:22:\"vb_login_password_hint\";s:13:\"Mot de passe \";s:1:\"s\";s:0:\"\";s:13:\"securitytoken\";s:5:\"guest\";s:20:\"vb_login_md5password\";s:32:\"d41d8cd98f00b204e9800998ecf8427e\";s:24:\"vb_login_md5password_utf\";s:32:\"d41d8cd98f00b204e9800998ecf8427e\";s:3:\"api\";N;s:1:\"a\";N;s:6:\"postid\";N;s:8:\"threadid\";N;s:7:\"forumid\";N;s:6:\"pollid\";N;}', '81.65.196.72', '81.65.196.72');

MySQL Error : Duplicate entry '5b608da55a806e31069c1c92443f8ef6' for key 'PRIMARY'
Error Number : 1062
Request Date : Thursday, September 12th 2013 @ 11:50:34 AM
Error Date : Thursday, September 12th 2013 @ 11:50:34 AM
Script : http://www.mysite.com/forum/login.php?do=login
Referrer : http://www.mysite.com/forum/forum.php
IP Address : ********************
Username : Non inscrit
Classname : vB_Database
MySQL Version :

the second error

Database error in vBulletin :

mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Access denied for user 'eb_db'@'localhost' (using password: YES)
/home/eb/public_html/forum/includes/class_core.php on line 317

MySQL Error :
Error Number :
Request Date : Thursday, September 12th 2013 @ 03:20:56 PM
Error Date : Thursday, September 12th 2013 @ 03:20:56 PM
Script : http://mysite.com/forum/showthread.php?t=74652
Referrer : http://www.mysite.com/forum/forumdisplay.php?f=157
IP Address : ***************
Username :
Classname : vB_Database
MySQL Version :

thank you for your help