iChat disconnects and reconnects

Hello I am new to the mac world. I bought a mac book about 2 weeks ago and I also moved into a new house where we set up a cox internet connection. I set up my wireless router so that everyone in the house can use it and it has been working o.k. for the most part. The problem is that when I try to sign on to iChat it disconnects and reconnects repeatedly until I am logged out. When I plug into the wall (with the crappy internet my community provides) I am able to sign on to AIM. I am not sure if this is a problem with my computer, my router, or my cox internet connection. Does anyone have any insight or know who I should contact for help?

thanks.