******this is error********
Warning: Wrong parameter count for mysql_connect() in .../class/adodb/drivers/adodb-mysql.inc.php on line 190 

*****this is the script that I use ******
include 'class/adodb.php'
$db = ADONewConnection('mysql'); 
/*here*/$db->Connect($db_host, $db_user, $db_password, $db_name)

Then I opened to the file adodb-mysql.inc.php to review it and if you see the error happens in 190 line of adodb v3.00 and 211 line in adodb v3.31, as they are equal in both cases only you I show it once.

function _connect($argHostname, $argUsername, $argPassword, $argDatabasename) 
{ 
global $ADODB_PHPVER; 
if ($ADODB_PHPVER >= 0x4300) 
$this->_connectionID = mysql_connect($argHostname,$argUsername,$argPassword, 
/*in this line  it happens the error */$this->forceNewConnect,$this->clientFlags); 


I have PHP 4.3.0 and MySQL 3.23.37