An error was encountered when compiling CTREEACU.C with MS Visual Studio C++ 6.0 "error C2065: 'DWORD_PTR': undeclared identifier." The logic has been corrected to eliminate this error: The DWORD_PTR type is defined as DWORD* if MAXULONG_PTR is not defined (see http://stackoverflow.com/questions/2723284/how-to-detect-if-the-windows-dword-ptr-type-is-supported-using-an-ifdef).