I assume this was working. There are some modifications that needed to be done to those files, however it's not likely they got changed on a PC that had been working. It may be time to replace it, however you will need to find an old DOS PC. You could try reloading one of the command files to see if that works, but it's most likely the PC.
Have you tried another keyboard? Reboot?
As for the instructions on how to set up and modify the old DOS MAT terminal, I think I have that information, however it will take me some time to find it. Maybe someone else has it readily available.