Thanks for the reply Lulu.
I initially got these error messages
MazeLibrary.pas(141,5) Error: Identifier not found "Stack"
MazeLibrary.pas(215,9) Error: Identifier not found "Stack"
MazeLibrary.pas(225,10) Error: Identifier not found "Stack"
MazeLibrary.pas(225,21) Warning: Conversion between ordinals and pointers is not portable
MazeLibrary.pas(226,10) Error: Identifier not found "Stack"
MazeLibrary.pas(226,21) Warning: Conversion between ordinals and pointers is not portable
MazeLibrary.pas(231,7) Fatal: Syntax error, "UNTIL" expected but "END" found
And then I found the problem Stack did not have a data type declared in the Variables
Var Stack: TStack;
Now everything compiles OK under 64bits. Thanks Lulu for the converted bits. Fantastic.