diff --git a/user.inc.php b/user.inc.php
index 9e432c0..3e4d4b6 100644
--- a/user.inc.php
+++ b/user.inc.php
@@ -472,7 +472,7 @@ function user_dupe_row($db, $key, $val, $newval)
 
 	foreach($i as $k=>$v) {
 		if($v == NULL && in_array($k, $nullfields)) 
-			$i[$k] = NULL;
+			$i[$k] = 'NULL';
 		else if($k == 'year') 
 			$i[$k] = $config['FAIRYEAR'];
 		else