Get Value of XML

I have been testing a lot of XML parser function but I had no success extracting the value. I wonder what went wrong. I want to get the value of STATUS_DESC AND STATUS_CODE in XML.

XML doc

$xml=" <?xml version="1.0" encoding="utf-8"?> 
<string xmlns="http://service.xxx/">
<ErrorInfo>
<STATUS_CODE>0105</STATUS_CODE>
<REQUEST_TIME>11/28/2014 4:03:10 AM</REQUEST_TIME>
<TIME_INTERVAL>300</TIME_INTERVAL>
<STATUS_DESC>Unable to fetch Data </STATUS_DESC>
</ErrorInfo>
</string>";

PHP

<?php
$xml=simplexml_load_string($xml);

var_dump($xml); 
// var_dump result:
//    object(SimpleXMLElement)#25 (1) { [0]=> string(48) "010511/28/2014 3:54:06 AM300Unable to fetch Data" } 
$error=$xml->ErrorInfo; 
$error1=$xml->ErrorInfo->STATUS_DESC;
echo $error; // Nothing
echo $error1; // Nothing

?>