I have looked at your project files but I cannot detect anything wrong.
There are missing MODULEs (initially GLOBAL and WINTERACTER) and a missing file (winparam.h) so I cannot get to the critical linking stage.
The project does point to an error in Plato3 because it is adding /REF to the FTN95 command line which should not happen for a Win32 project. This is giving a spurious 'missing library' error. I have fixed this for the next release.
I notice that you are selecting /CHECK etc as well as /CHECKMATE. It is just possible that FTN95 is getting confused by the mix of options.
Try using the default options first to see what happens. The default for CHECKMATE mode is /CHECKMATE. All of the following (that you automatically get with /CHECKMATE) can be omitted: /DEBUG, /CHECK, /UNDEF, /BOUNDS_CHECK.
/QUICK_BOUNDS is obsolete and has no effect.
I suggest that you start with a new project, use the default options, and add files one at a time, compiling as you go along. My guess is that it will be OK until you change the options. If you change options one at a time and build each time, then you will probably be able to find the option that is causing the problem.
If this does not solve the problem then I will either need the missing files and libraries or I will need a simpler project that demonstrates the problem but does not need these files.
Regards
Paul