diff --git a/Open-ILS/web/js/ui/default/actor/user/register.js b/Open-ILS/web/js/ui/default/actor/user/register.js
index 3fe41b8..cc4ee2e 100644
--- a/Open-ILS/web/js/ui/default/actor/user/register.js
+++ b/Open-ILS/web/js/ui/default/actor/user/register.js
@@ -344,9 +344,11 @@ function replaceCardHandler() {
     replaceBarcode.attr('disabled', true);
     
     // pull old card off the cards list so we don't have a dupe sitting in there
-    var old = patron.cards().filter(function(c){return (c.id() == patron.card().id())})[0];
-    old.active('f');
-    old.ischanged(1);
+    if (patron.cards().length > 0) {
+        var old = patron.cards().filter(function(c){return (c.id() == patron.card().id())})[0];
+        old.active('f');
+        old.ischanged(1);
+    }
 
     var newc = new fieldmapper.ac();
     newc.id(uEditCardVirtId--);