thanks, that already helped a lot.. (the DllCpp was the problem, #define over there instead above the header..) Since multiple header files all include this one (Engine.h), I get several (7) Errors Error LNK2005: "void (__cdecl* Engine::Input::on_a)(void)" (?on_a@Input@Engine@@3P6AXXZA) already defined in Engine.obj LuaScriptor.obj But I think I can get around that problem, or just by simply putting everything inside a single header and source file. Thanks to all for the support and the quick help :) EDIT: Fixed all (Copy everything to Engine.cpp and Engine.h), thanks modified on Sunday, April 27, 2008 6:10 PM