Index: branches/5.1.x/core/units/helpers/curl_helper.php
===================================================================
diff -u -N -r14241 -r14325
--- branches/5.1.x/core/units/helpers/curl_helper.php	(.../curl_helper.php)	(revision 14241)
+++ branches/5.1.x/core/units/helpers/curl_helper.php	(.../curl_helper.php)	(revision 14325)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: curl_helper.php 14241 2011-03-16 20:24:35Z alex $
+* @version	$Id: curl_helper.php 14325 2011-05-20 08:10:28Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -132,13 +132,16 @@
 				// hardcoded options
 				CURLOPT_RETURNTRANSFER => 1,
 				CURLOPT_REFERER => PROTOCOL.SERVER_NAME,
-				CURLOPT_USERAGENT => $_SERVER['HTTP_USER_AGENT'],
-				
+
 				// don't verify SSL certificates
 				CURLOPT_SSL_VERIFYPEER => false,
 				CURLOPT_HTTPHEADER => Array ('Expect:'),
 			);
 
+			if ( isset($_SERVER['HTTP_USER_AGENT']) ) {
+				$default_options[CURLOPT_USERAGENT] = $_SERVER['HTTP_USER_AGENT'];
+			}
+
 			if ($this->requestHeaders) {
 				$default_options[CURLOPT_HTTPHEADER] = $this->prepareHeaders();
 			}