Index: trunk/core/units/user_groups/user_groups_config.php
===================================================================
diff -u -N -r7855 -r8015
--- trunk/core/units/user_groups/user_groups_config.php	(.../user_groups_config.php)	(revision 7855)
+++ trunk/core/units/user_groups/user_groups_config.php	(.../user_groups_config.php)	(revision 8015)
@@ -50,7 +50,7 @@
 					'Fields'			=>	Array(
 						'PortalUserId'				=>	Array('type' => 'int', 'not_null' => 1, 'default' => 0),
 						'GroupId'					=>	Array('type' => 'int', 'not_null' => 1, 'default' => 0),
-						'MembershipExpires' 		=> Array('type' => 'int', 'formatter' => 'kDateFormatter', 'default' => ''),
+						'MembershipExpires' 		=> Array('type' => 'int', 'formatter' => 'kDateFormatter', 'default' => null),
 						'PrimaryGroup'				=>	Array('type' => 'int', 'formatter' => 'kOptionsFormatter', 'options' => Array (1 => 'la_Yes', 0 => 'la_No'), 'use_phrases' => 1, 'not_null' => 1, 'default' => 1),
 						'ExpirationReminderSent'	=>	Array('type' => 'int', 'not_null' => 1, 'default' => 0),
 									        ),