执行（）时PHP PDO出错

I am attempting to insert data into database via PDO

Here is my snippet:

try {
        $count = count($db_data);
        for ($i=0; $i < $count ; $i++) { 
            $query_string = "INSERT INTO data (" . $fields[$i] . ") VALUES(" . $values[$i] . ")";
            echo $query_string;
            $vle = $dbh->prepare($query_string);

            $vle->bindValue(':USER', $db_data[$i]['user']);
            $vle->bindValue(':SERVER_NAME', $db_data[$i]['server_name']);
            $vle->bindValue(':SERVER_NAME', $db_data[$i]['description']);
            $vle->bindValue(':PATH', $db_data[$i]['path']);
            $vle->bindValue(':DATE', $db_data[$i]['date']);
            $vle->execute();

            echo "KEY: " . $fields[$i] . "</br>" . "VALUES: " . $values[$i] . "</br>";
        }

    } catch (PDOException $e) {
        echo $e->getMessage();
    }
}

But I am getting following error:

Warning: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens in

EDIT

$query_string is:

INSERT INTO data (user, server_name, description, path, date) VALUES(:jsieclaf, :srvc07.gnotek.com>, :php.nested.base64.526, :a:1:{i:0;s:70:" /home/jsieclaf/public_html/modules/mod_araticl= hess/mod_araticlhess";}, :Mon, 7 Apr 2014 13:48:56 +0300)

$db_data is:

array (size=5)   

'user' => string ':jhjju' (length=9)   
'server_name' => string ':sjvbg07.gnotek.com>' (length=20)   
'description' => string ':php.nested.bade454.526' (length=22)   
'path' => string ':a:1:{i:0;s:70:" /home/jhjju/public_html/modules/mod_araticl=     hess/mod_ereticlhess";}' (length=89)   
'date' => string ':Mon, 7 Apr 2014 13:48:56 +0300' (length=31)

$sql = "INSERT INTO $tableName (" . implode(',', array_keys($assoc_array)) . ") VALUES (" . trim(str_repeat('?,', count($assoc_array)), ',') . ")";

$stm = $dbh->prepare($sql);
$stm->execute(array_values($assoc_array));

try {
    $sql = "INSERT INTO $tableName (" . implode(',', array_keys($assoc_array)) . ") VALUES (" . trim(str_repeat('?,', count($assoc_array)), ',') . ")";
    $stm = $db->prepare($sql);
    $stm->execute(array_values($assoc_array));

} catch (PDOException $e) {
  echo $e->getMessage();
}