All of the files in this directory are for use with Microsoft Visual C++ 4.0 On my system these files are located in the C:\PCE32\Msoft directory. If you have problems compiling the files move the files to this directory. Note I have renamed the Microsoft source code to PCE32DLL.DLL instead of PCE32.DLL , make sure that if you use the Microsoft compiler you alter the Visual Basic files to reflect this change.