Powdertoy Compile Error

1>  Generating Code...
1>ElementClasses.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall Element_TEST::~Element_TEST(void)" (??1Element_TEST@@UAE@XZ) referenced in function "class std::vector<class Element,class std::allocator<class Element> > __cdecl GetElements(void)" (?GetElements@@YA?AV?$vector@VElement@@V?$allocator@VElement@@@std@@@std@@XZ)
1>ElementClasses.obj : error LNK2019: unresolved external symbol "public: __thiscall Element_TEST::Element_TEST(void)" (??0Element_TEST@@QAE@XZ) referenced in function "class std::vector<class Element,class std::allocator<class Element> > __cdecl GetElements(void)" (?GetElements@@YA?AV?$vector@VElement@@V?$allocator@VElement@@@std@@@std@@XZ)
1>C:\The-Powder-Toy-Source\Build\TheElementToy.exe : fatal error LNK1120: 2 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========