Don't know if this'll help you at all, but generally if the problem was that VS couldn't find the header file you would get an error along the lines of:

"Warning C4013: 'my_func' undefined; assuming extern, returning int"

Another way that you can get an idea of whether the issue is a compiler or a linker problem is by looking at the error codes. Compiler problems start with Cxxxx whereas linker problems start with LNKxxxx.

A good way to get help on these problems is to search by that error code.

Cheers,
ac