pokrchamp is probably right. TCP has a lot more overhead than UDP and is inherently slower due to all of these extra checks and controls. Plug your internet connection directly into your PC and try UDP. It seems to me like TCP just isn't going to work for you guys so you have to figure out UDP.
For next season I strongly believe we need to make UDP a requirement to be in the league. Guys, I realize it can be a bit intimidating and/or confusing, but please put forth an effort to set up port forwarding or DMZ on your router so you can play with UDP.
Schwartz spent the time to do up a nice little getting started page that explains the basics of port forwarding. - http://www.nhl94online.com/html/snes-zbattle-howto.shtml
So take a look at that and see if you can't get port forwarding set up properly. As a quick and dirty explanation of why port forwarding is required for UDP...
Think of the online data between you and your opponenet as mail that is labelled with your address, but without a name. It's easy enough to get the letter to your house , but who in the house is the letter for? The router knows that UDP data has been delivered, but it doesn't know which computer on your local network it is for. By forwarding port 7845 (this is the port that ZSNES uses) to the computer you plan to play on, your router knows that when it receives data on port 7845 it should be sent to your computer.
I know 1 big thing that confuses a lot of people are the IP Addresses. To figure out what your **LOCAL** IP Address is do the following:
1. Click the Start button and select Run (this will open a little window with a text box)
2. In the text box, type cmd and hit the Enter key (this will open a black DOS window)
3. In the black window type ipconfig and press the Enter key.
4. There will be a few IP addresses displayed, but the one you are looking for will actually be labelled IP Address (not Subnet Mask or Default Gateway). It will probably start with a 192.168 .
This is the address you want to forward port 7845 to. The next step is to set up the port forwarding on your router (this step will vary depending on the type of router you have... Schwartz put a few links to some of the more common routers in his getting started page). And remember, after you set up or change the port forwarding you usually have to restart your router before the changes will take effect.
That is really all you should have to do to play with UDP.