check if http_response_header is defined

include/functions.php

@@ -394,6 +394,7 @@
 			$data = @file_get_contents($url);
 
 			$fetch_last_content_type = false;  // reset if no type was sent from server
+			if (is_array($http_response_header)) {
 				foreach ($http_response_header as $h) {
 					if (substr(strtolower($h), 0, 13) == 'content-type:') {
 						$fetch_last_content_type = substr($h, 14);
@@ -401,6 +402,7 @@
 						// e.g. if we were being redirected -- last one is the right one
 					}
 				}
+			}
 
 			if (!$data && function_exists('error_get_last')) {
 				$error = error_get_last();