Database error in vBulletin

[fireboxssl]

Can anyone help me out with this error:

Database error in vBulletin :

mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Too many connections
/var/www/vhosts/xxxxx.com/httpdocs/includes/class_core.php on line 311

and

mysql_connect() [<a href='function.mysql-connect'>function.mysql-connect</a>]: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
/var/www/vhosts/xxxxx.com/httpdocs/includes/class_core.php on line 311

Thanks

[Dismounted]

vBulletin Manual: Common MySQL Error Messages (See "Too many connections")
vBulletin Manual: Can't connect to local MySQL server through socket

[fireboxssl]

Thank you