--- a/modules/plugin/base/src/nsNPAPIPlugin.cpp
+++ b/modules/plugin/base/src/nsNPAPIPlugin.cpp
@@ -2453,31 +2453,31 @@ void* NP_CALLBACK /* OJI type: jref */
 
 void NP_CALLBACK
 _pushpopupsenabledstate(NPP npp, NPBool enabled)
 {
   if (!NS_IsMainThread()) {
     NPN_PLUGIN_LOG(PLUGIN_LOG_ALWAYS,("NPN_pushpopupsenabledstate called from the wrong thread\n"));
     return;
   }
-  nsNPAPIPluginInstance *inst = (nsNPAPIPluginInstance *)npp->ndata;
+  nsNPAPIPluginInstance *inst = npp ? (nsNPAPIPluginInstance *)npp->ndata : NULL;
   if (!inst)
     return;
 
   inst->PushPopupsEnabledState(enabled);
 }
 
 void NP_CALLBACK
 _poppopupsenabledstate(NPP npp)
 {
   if (!NS_IsMainThread()) {
     NPN_PLUGIN_LOG(PLUGIN_LOG_ALWAYS,("NPN_poppopupsenabledstate called from the wrong thread\n"));
     return;
   }
-  nsNPAPIPluginInstance *inst = (nsNPAPIPluginInstance *)npp->ndata;
+  nsNPAPIPluginInstance *inst = npp ? (nsNPAPIPluginInstance *)npp->ndata : NULL;
   if (!inst)
     return;
 
   inst->PopPopupsEnabledState();
 }
 
 class nsPluginThreadRunnable : public nsRunnable,
                                public PRCList