If u've a torrent file, open it up in Azuerus... sometimes Azuerus can show NAT error when there's no seeding available or the torrents source file no longer exists... if u still get NAT error, double click on where it says NAT error.. it should open up a wiki and the tab where u can change the port number... just select anything over 8000 or something like that.. read the webpage that opens up when u click on NAT error on the bottom of the Azuereus... that should fix it... don't try to get too complicated... cuz the tool itself can be setup w/ very complexity and I haven't figured all out myself either.. if u r using wireless router, then u might need to do port forward, but if it's a direct line to cable/dsl, u should be ok w/ the defaul port that's with Azureus... google it.. lots of help there also.... hope it helps.