This has worked for me and a few others I helped:
1. Under Tools>Options>Directories>Show Directories for:>Include files, add the directory that contains Steve Heller's includes (e.g., c:\djgpp\whos\code or similar)
2. Under Tools>Options>Directories>Show Directories for:>Library files, add the directory that contains Steve Heller's stharch.a library (e.g., c:\djgpp\lib or similar)
3. Place your project files into the Visual C++ project directory (e.g., C:\Program Files\DevStudio\MyProjects\WAoCpp\basic02). You do not need to move the header and library files -- we took care of them in steps one and two.
4. Insert the project's .cc files into the project using Project>Add to Project>Files...
I think this is where you had your problems last time -- you may have forgotten to insert string6.cc into the project. This file is the implementation of the string6.h file, so it will certainly need to be compiled with the project.
5. You can leave the header and library files in their respective directories, a you told Visual C++ where to find them in steps one and two above.
This method works and is easier to use than my last Email's method. Good luck.