diff --git a/modules/plugin/base/src/ns4xPlugin.cpp b/modules/plugin/base/src/ns4xPlugin.cpp
index 261eb602ced..a33c2d95662 100644
--- a/modules/plugin/base/src/ns4xPlugin.cpp
+++ b/modules/plugin/base/src/ns4xPlugin.cpp
@@ -1471,7 +1471,7 @@ doGetIdentifier(JSContext *cx, const NPUTF8* name)
                                        utf16name.Length());
 
   if (!str)
-    return nsnull;
+    return NULL;
 
   return (NPIdentifier)STRING_TO_JSVAL(str);
 }
@@ -1479,6 +1479,11 @@ doGetIdentifier(JSContext *cx, const NPUTF8* name)
 NPIdentifier NP_CALLBACK
 _getstringidentifier(const NPUTF8* name)
 {
+  if (!name) {
+    NPN_PLUGIN_LOG(PLUGIN_LOG_ALWAYS, ("NPN_getstringidentifier: passed null name"));
+    return NULL;
+  }
+
   nsCOMPtr<nsIThreadJSContextStack> stack =
     do_GetService("@mozilla.org/js/xpc/ContextStack;1");
   if (!stack)
@@ -1510,7 +1515,13 @@ _getstringidentifiers(const NPUTF8** names, int32_t nameCount,
   JSAutoRequest ar(cx);
 
   for (int32_t i = 0; i < nameCount; ++i) {
-    identifiers[i] = doGetIdentifier(cx, names[i]);
+    if (names[i]) {
+      identifiers[i] = doGetIdentifier(cx, names[i]);
+    } else {
+      NPN_PLUGIN_LOG(PLUGIN_LOG_ALWAYS, ("NPN_getstringidentifiers: passed null nam
+e"));
+      identifiers[i] = NULL;
+    }
   }
 }