Host problem or code problem ?

[launcher]

Hi everyone.
I have created a website on Flex builder 3 and it works fine on my local server,
but when I upload it to my host i get this error from flex.

Error [RPC Fault faultString="Security error accessing url" faultCode="Channel.Security.Error" faultDetail="Destination: DefaultHTTP"]

And the php files doesn't return any information.

I try to use crossdomain policy but it doesn't work.
here's my php file that returns the xml.

PHP Code:

<?php
    require_once("config.php");

    class infoRetrieve
    {
        private $connection;
        
        function infoRetrieve($table_name)
        {
            $this->conn();
            mysql_query("SET NAMES utf8");
            $query = $this->selectAllQuery($table_name);
            $xml = $this->returnXML($query);
            print_r($xml);
        }
        
        public function conn()
        {
            $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS);
            if(!$this->connection)
            {    
                die("database connection faled" . mysql_error());
            }
            else
            {
                $db_select = mysql_select_db(DB_NAME, $this->connection);
                if(!$db_select)
                {
                    die("database selecition faled" . mysql_error());
                }
            }    
        }
        
        public function selectAllQuery($table_name)
        {
            if(isset($table_name))
            {
                $query = mysql_query("SELECT * FROM {$table_name}");
            }
            return $query;
        }
        
        public function returnXML($info)
        {
            $xml = "<root>";
        
            if(isset($info))
            {
                while($row = mysql_fetch_array($info))
                {
                    for($i = 0; $i < (count($row)/2); $i++)
                    {
                        $xml .= "<item{$i}>";
                            $xml .= $row[$i];
                        $xml .= "</item{$i}>";
                    }
                }
            }
            else 
            {
                echo "Error";
            }
            
            
            $xml .= "</root>";
            
            return $xml;
        }
        
        public function closeConn()
        {
            if(isset($this->connection))
            {
                mysql_close($this->connection);
                unset($this->connection);
            }
        }
    }
?>

The php version on my local servar is 5.
On host server is 4. Can this be the problem ?