When using simplexml to access a element the returned object may be a SimpleXMLElement instead of a string.
Example:
<?php
$string = <<<XML
<?xml version='1.0'?>
<document>
    <cmd>login</cmd>
    <login>Richard</login>
</document>
XML;
                                                                        
                                           
$xml = simplexml_load_string($string);
print_r($xml);
$login = $xml->login;
print_r($login);
$login = (string) $xml->login;
print_r($login);
?>
Expected result:
----------------
SimpleXMLElement Object
(
    [cmd] => login
    [login] => Richard
)
Richard
Richard
Actual result:
--------------
SimpleXMLElement Object
(
    [cmd] => login
    [login] => Richard
)
SimpleXMLElement Object
(
    [0] => Richard
)
Richard
But this is an intended behavior. See http://bugs.php.net/bug.php?id=29500