I got this error from a swf file:

Code:
Error: Error #1502: at classes::Window_common_chat/__setProp___id1__window_common_chat_btns_0()
	at classes::Window_common_chat()
	at flash.display::Sprite/constructChildren()
	at flash.display::Sprite()
	at flash.display::MovieClip()
	at classes::Ingame_interface()
	at classes::Main()
But I don't have a function called __setProp___id1__window_common_chat_btns_0.
What is this setProp about? Must be something from within flash?