Replaced every use of lua_call with RunScriptOnStack. Modified RunScriptOnStack to report an error to log and system message using a passed in context string. Modified every use of RunScriptOnStack to avoid crashing so that the reported error can be seen.

src/LuaExpressionTransform.cpp

@@ -26,7 +26,8 @@ void LuaExpressionTransform::TransformItemDirect( Actor &a, float fPositionOffse
 	LuaHelpers::Push( L, fPositionOffsetFromCenter );
 	LuaHelpers::Push( L, iItemIndex );
 	LuaHelpers::Push( L, iNumItems );
-	lua_call( L, 4, 0 ); // 4 args, 0 results
+	RString error= "Lua error in Transform function: ";
+	LuaHelpers::RunScriptOnStack(L, error, 4, 0, true);
 	LUA->Release(L);
 }