Index: lib/GeoExt/data/WMSCapabilitiesStore.js
===================================================================
--- lib/GeoExt/data/WMSCapabilitiesStore.js	(revision 945)
+++ lib/GeoExt/data/WMSCapabilitiesStore.js	(working copy)
@@ -40,6 +40,7 @@
  */
 
 GeoExt.data.WMSCapabilitiesStore = function(c) {
+    c = c || {};
     GeoExt.data.WMSCapabilitiesStore.superclass.constructor.call(
         this,
         Ext.apply(c, {