Same baud rate selected on both sides? What's the complete error message?

the actual message is

"Serial1: errors occurred: Framing 0, Parity 0, Overrun 10, <IFO:0>, Break 0"

This is the message that repeats while I am attempting to link both games, when the link begins the first message has overrun as 2, and then it follows as I wrote it above.

Oh damn, this thing is for modem only. And has only a few digits for the phone number. And numbers only.

Does this mean, I will not be able to play multiplayer with it?

I know on my older computer back in the day I used to play with my father using a null modem cable. The virtual null modem cable just doesn't seem to be working.

There doesn't seem to be an option for nullmodem in the game? Is there a trick?

Not that I know of, it was a long time since I have played it, I thought a null modem cable just simulated a modem, So I was just originating on one and auto-answer on the other, something must of have been happening because those errors were registering in the answering side.

I found the manual and this is what it says,

Using a Null Modem Cable

You can also play a modem game using a "null modem". A null modem is
a cable that transmits information from your computer's communication
port to that of your opponent's. You don't need modems at all when you use
a null modem cable -- however, the two computers must each have a free
serial port connection and be near enough to connect with the null modem
cable. Ask your computer dealer for details on where you can get a null
modem cable. (See Appendix A for the specific wiring information.)

Preliminaries (both parties): With your computers off, connect the two
computers with the null-modem cable. Turn on the computers, load the
game, and go to the CONFIGURATION PANEL. Select the communication
(serial) port your null-modem line is connected to (MODEM GAME ON COM
1: or MODEM GAME ON COM2:).

What the originator does:

1. Select MISSION SELECTION and choose the mission. The side that you
(the originator) selects the side you'll play.
2. Select ORIGINATE.

What the answerer does:

1. Wait for the other player to "originate" the contact.
2. Select MANUAL ANSWER.

Well, tried a few things but doesn't work here either...

Alright, well thank you for your efforts

Is this the original copy of your game, that is the one from which you know
it supports nullmodem gameplay?

yes it is