Here's step by step what I'm doing:
First off, note that I have the Multisync .dll, client.exe and host.exe placed on the desktop. Also note that i'm connected to the internet and have set all programs listed above to be allowed by the firewall. I also have the Multisync.dll inside the user-plugins folder aswell.
1. Open whatismyip.com
2. Click host.exe
3. Enter exact ip given from whatismyip.com
4. Hit enter, I'm now in the game moving a red cube around a matrix
5. Click client.exe
6. Enter exact ip given from whatismyip.com that I entered before
7. Hit enter, wait a few seconds, see FAILED display under the input command, wait a few more seconds and the client.exe closes.
8. Throw a hissy fit and break my keyboard
9. Load up on tylenols
Also, not sure if this is relevant but when I run the host.exe, it says "Player Exists? : 0" on the screen.
<EDIT>
Also, Im absolutely positive that 1. I'm using the correct IP and 2. that I'm entering the correct IP (So no spelling mistakes) both times.
Im gona go try this downstairs on my other computer, Ill get back to you with the results in a few minutes.