Close MYSQL Connection??

Hi I update my website, whit ezSQL, but i have a problem whith a connection. When my site supports 45 online users the connection lost. And the apache error log says:

[error] PHP Warning: Error establishing mySQL database connection. Correct user/password? Correct hostname? Database server running? in /home/...page.php on line 79

PHP Warning: mysql_connect(): User **** has already more than 'max_user_connections' active connections in /home/......page.php on line 25

There are any way to close the connection when the page has finised?

example;

-start page-
include("ezMYSQl..");

-contents page--
$db->query("SELECT A.....")
$db->query("SELECT B.....")
$db->query("SELECT C.....")
$db->query("SELECT D.....")

-finish page-
$db->CloseConection(); Or similar??

tanks
nicolas