Index: branches/5.1.x/core/install/upgrades.php
===================================================================
diff -u -N -r14241 -r14327
--- branches/5.1.x/core/install/upgrades.php	(.../upgrades.php)	(revision 14241)
+++ branches/5.1.x/core/install/upgrades.php	(.../upgrades.php)	(revision 14327)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: upgrades.php 14241 2011-03-16 20:24:35Z alex $
+* @version	$Id: upgrades.php 14327 2011-05-20 08:14:24Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -227,11 +227,13 @@
 				'<inp:topic _field="link" _Template="inbulletin/post_list"' => '<inp2:bb_TopicLink template="__default__"',
 			);
 
-			foreach ($replacements as $old_tag => $new_tag) {
-				$sql = 'UPDATE '.TABLE_PREFIX.'EmailMessage
-						SET Template = REPLACE(Template, '.$this->Conn->qstr($old_tag).', '.$this->Conn->qstr($new_tag).')
-						WHERE EventId IN ('.$event_ids.')';
-				$this->Conn->Query($sql);
+			if ($event_ids) {
+				foreach ($replacements as $old_tag => $new_tag) {
+					$sql = 'UPDATE '.TABLE_PREFIX.'EmailMessage
+							SET Template = REPLACE(Template, '.$this->Conn->qstr($old_tag).', '.$this->Conn->qstr($new_tag).')
+							WHERE EventId IN ('.$event_ids.')';
+					$this->Conn->Query($sql);
+				}
 			}
 
 			if ($mode == 'after') {