There are several things you can look at there to avoid the multiple inclusion of these .
You might want to use an ifndef block to enclose the contents of your header file
(see the b.h example in
http://www.cplusplus.com/forum/beginner/7877/ )
or use
#pragma once http://en.wikipedia.org/wiki/Pragma_once
to avoid it
The other thing you can look are the header settings for your VC -- Is it set to use pre-compiled headers? -- if so you could change the option
If your program is set up so that you can include this header for only one of the cpp files you can remove it from stdafx and include it for that cpp file only.