I have a problem when running my application on a certain machine I'm getting a
"Stack Overflow" error message, and on any other machine it gives no problem.

I turned on the {$S+} switch and it didn't help.

Does anyone out there know what causes this problem, please give me a post

You define the boolean as a private object-variable; therefore you know
it is initially false.  Now in your method you do:

        if not boolean_flag then begin
          try
            boolean_flag := true;
            << original method >>
          finally
            boolean_flag := false;
          end;
        end;