insert Records stops working suddenly - PHP - help please

Well, all this code worked last week and all of a sudden it doesn't work at all anymore. I get a error 4500 (general error) which doesn't help me much. here's the code:

$url = "http://crm.zoho.com/crm/private/xml/Leads/insertRecords?loginName=rene@bench-mark.ca&newFormat=1&apikey=".$apiKey."&ticket=".$ticket;
    $xml = '<?xml version="1.0" encoding="UTF-8" ?><Leads>'
                     .'<row no="1">';
        foreach($data as $k => $v){
        if ($v != "") {
            $v = str_replace("&", "And", $v);
            $xml .= '<FL value="'.$k.'">'.$v.'</FL>';
        }
        }
    $xml    .= '</row>';
    $xml    .= '</Leads>';

    //open connection
    $ch = curl_init();

    //set the url, number of POST vars, POST data
    curl_setopt($ch,CURLOPT_URL,$url);
    curl_setopt($ch,CURLOPT_POST,1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // tell curl to return data in a variable
    curl_setopt($ch,CURLOPT_POSTFIELDS, 'xmlData='.$xml);
    //execute post
    $result = curl_exec($ch);
    curl_close($ch);
        return $result;