If the lights come on, that's a good sign. Doesn't mean the adaptor is working for sure, but it's a start.
Next thing is to make sure everything is set up correctly in the network adapter screen ('external adapter' is what I seem to recall it says on that screen). Make sure you understand how IP networking works, and set the proper IP address and netmask for the Central in that screen. Then see if you can ping it.
If you can ping it, then the network adapter is working and all you have to do is get the configuration right. I seem to recall someone else on this BBS getting stuck because there's a setting somewhere in the networking screens about allowing emplode to connect via ethernet and/or setting the ethernet password for emplode. So make sure that's set, too.
If you still can't get it to work, please post details of all your network settings (PC, Jemplode, and Central) and your network topology (hubs routers cabling etc).