diff --git a/src/scripting/flashutils.cpp b/src/scripting/flashutils.cpp
index 1192162..2bb7cdb 100644
--- a/src/scripting/flashutils.cpp
+++ b/src/scripting/flashutils.cpp
@@ -746,16 +746,19 @@ ASFUNCTIONBODY(lightspark,getDefinitionByName)
 ASFUNCTIONBODY(lightspark,describeType)
 {
 	assert_and_throw(argslen==1);
 
 	//HACK: TODO: support classes. YouTube needs this
 	if(args[0]->getObjectType()==T_CLASS)
 		return new Undefined;
 
+	if(args[0]->getObjectType()==T_UNDEFINED)
+		return new Undefined;
+
 	Class_base* type=args[0]->getPrototype();
 	assert_and_throw(type);
 	//TODO: add support in type for base, isDynamic, isFinal, isStatic
 	string ret = "<type name=\"";
 	if(type->class_name.ns.len())
 	{
 		ret+=type->class_name.ns.raw_buf();
 		ret+=".";