parser error : Start tag expected, '<' not found

The code you refer to has this line:

//curl_setopt($connection, CURLOPT_HEADER, 1 ); // Uncomment these for debugging

it seems like you uncommented these. This will result in getting the HTTP header in your response. Which is OK for debugging, but it will create an XML parse error in simplexml_load_string.

Either comment it out again or put 0 as its value.