diff --git a/includes/User.php b/includes/User.php
index 44dada4ef6c..18475fdd283 100644
--- a/includes/User.php
+++ b/includes/User.php
@@ -1575,13 +1575,15 @@ class User {
 	function addGroup( $group ) {
 		$this->load();
 		$dbw =& wfGetDB( DB_MASTER );
-		$dbw->insert( 'user_groups',
-			array(
-				'ug_user'  => $this->getID(),
-				'ug_group' => $group,
-			),
-			'User::addGroup',
-			array( 'IGNORE' ) );
+		if( $this->getId() ) {
+			$dbw->insert( 'user_groups',
+				array(
+					'ug_user'  => $this->getID(),
+					'ug_group' => $group,
+				),
+				'User::addGroup',
+				array( 'IGNORE' ) );
+		}
 
 		$this->mGroups[] = $group;
 		$this->mRights = User::getGroupPermissions( $this->getEffectiveGroups( true ) );
diff --git a/maintenance/deleteDefaultMessages.php b/maintenance/deleteDefaultMessages.php
index fdad54ca29a..76924002184 100644
--- a/maintenance/deleteDefaultMessages.php
+++ b/maintenance/deleteDefaultMessages.php
@@ -16,6 +16,8 @@ function deleteDefaultMessages() {
 
 	global $wgUser;
 	$wgUser = User::newFromName( $user );
+	$wgUser->addGroup( 'bot' );
+	
 	$dbr =& wfGetDB( DB_SLAVE );
 	$res = $dbr->select( array( 'page', 'revision' ),
 		array( 'page_namespace', 'page_title' ),