opening files with read and write access

Use chmod to set the permissions of the file so its writable. Then open it with write access, then after you write and close the file, use chmod again to change the permissions to read only.

eg:

@chmod ($configfile, 0755);
$xml_string = file_get_contents($filepath);
read_write_to_xml($xml_string);
if ($fp = fopen($filepath, 'w')) {
     fwrite($fp, $xml_string, strlen($xml_str);
     fclose($fp);
} else {
     echo 'Cannto write to file';
}
@chmod ($configfile, 0744);

Should do it. Unless you're on windows, then chmod wouldnt make any sense.

thank you, unfortunately yea I am on windows at work so chmod wont work but no big deal.

On windows try chmod 775 for non-writeable and 666 for writeable.
see: http://www.php.net/manual/en/function.chmod.php