My mistake was to use the Run Command (Windows Key + R) and not the Windows Command Prompt (found under the Windows System folder on the Windows 10 Start Menu). I think what was being displayed was RT2_Port's help instructions; which give much detail of the app's functions.
I have successfully modified a map file to fix the ports. Now, demand for goods at the port does not fall to zero after the first delivery. To achieve this I used the command: RT2_Port -fw <MapfileName>
This automatically fixes the map file and rewrites the data to the file. The Command Prompt app has to be