nat errors and trouble with ports

I've recently bought and downloaded sharing software called Azureus off of the internet. Now I've used Bearshare and Kazaa before and never had a problem, but when I try to use this software it tells me I'm not connecting to anyone who is sharing and that I'm have all closed ports or I'm experiencing NAT errors. I don't know what to do. I've tried opening ports through my internet connection and it says that they are all open. The software says that the router on my dsl modem might be causing the problem also, but like I said, I've never had any problems with any other sharing programs. I'm on Windows XP and I surf the internet through Earthlink via a Sprint DSL connection. It says I'm set up as a Local Are Network connection. also everytime I try to get help for my Windows xp software, the steps that people tell me to take aren't neccessarily available when I go to execute them. Please please please help me!

Azureus dosnt cost anything. its free. this isnt really a file sharing forum. i think you would do better at another forum, except the only one i know is very poor as far as help goes. i will provide some links if you want. a question: do you have a router and a dsl modem or just a dsl modem in place. with azureus open>tools>Nat Firewall test you might try changing the default port in azureus