php not show eror

<?php
require("phpajax_dbinfo.php");
 
// Start XML file, create parent node
$doc = domxml_new_doc("1.0");
$node = $doc->create_element("markers");
$parnode = $doc->append_child($node);
 
// Opens a connection to a MySQL server
$connection=mysql_connect (localhost, $username, $password);
if (!$connection) {
  die('Not connected : ' . mysql_error());
}
 
// Set the active MySQL database
$db_selected = mysql_select_db($database, $connection);
if (!$db_selected) {
  die ('Can\'t use db : ' . mysql_error());
}
 
// Select all the rows in the markers table
$query = "SELECT * FROM markers WHERE 1";  
$result = mysql_query($query);
if (!$result) {
  die('Invalid query: ' . mysql_error());
}
 
header("Content-type: text/xml");
 
// Iterate through the rows, adding XML nodes for each
while ($row = @mysql_fetch_assoc($result)){
  // ADD TO XML DOCUMENT NODE
  $node = $doc->create_element("marker");
  $newnode = $parnode->append_child($node);
 
  $newnode->set_attribute("name", $row['name']);
  $newnode->set_attribute("address", $row['address']);
  $newnode->set_attribute("lat", $row['lat']);
  $newnode->set_attribute("lng", $row['lng']);
  $newnode->set_attribute("type", $row['type']);
  $newnode->set_attribute("type", $row['picname']);
}
 
$xmlfile = $doc->dump_mem();
echo $xmlfile;
 
?>