Index: django/contrib/admin/media/js/admin/RelatedObjectLookups.js
===================================================================
--- django/contrib/admin/media/js/admin/RelatedObjectLookups.js	(revision 9368)
+++ django/contrib/admin/media/js/admin/RelatedObjectLookups.js	(working copy)
@@ -13,8 +13,9 @@
 
 function showRelatedObjectLookupPopup(triggeringLink) {
     var name = triggeringLink.id.replace(/^lookup_/, '');
-    // IE doesn't like periods in the window name, so convert temporarily.
-    name = name.replace(/\./g, '___');
+    // IE doesn't like periods or dashes in the window name, so convert temporarily.
+    name = name.replace(/\./g, '___dot___');
+    name = name.replace(/\-/g, '___dash___');
     var href;
     if (triggeringLink.href.search(/\?/) >= 0) {
         href = triggeringLink.href + '&pop=1';
@@ -27,7 +28,8 @@
 }
 
 function dismissRelatedLookupPopup(win, chosenId) {
-    var name = win.name.replace(/___/g, '.');
+    var name = win.name.replace(/___dot___/g, '.');
+    name = name.replace(/___dash___/g, '-');
     var elem = document.getElementById(name);
     if (elem.className.indexOf('vManyToManyRawIdAdminField') != -1 && elem.value) {
         elem.value += ',' + chosenId;
@@ -39,7 +41,8 @@
 
 function showAddAnotherPopup(triggeringLink) {
     var name = triggeringLink.id.replace(/^add_/, '');
-    name = name.replace(/\./g, '___');
+    name = name.replace(/\./g, '___dot___');
+    name = name.replace(/\-/g, '___dash___');
     href = triggeringLink.href
     if (href.indexOf('?') == -1) {
         href += '?_popup=1';
@@ -56,7 +59,8 @@
     // django.utils.html.escape.
     newId = html_unescape(newId);
     newRepr = html_unescape(newRepr);
-    var name = win.name.replace(/___/g, '.');
+    var name = win.name.replace(/___dot___/g, '.');
+    name = name.replace(/___dash___/g, '-');
     var elem = document.getElementById(name);
     if (elem) {
         if (elem.nodeName == 'SELECT') {