Did you set up port forwarding within your router, or did you just check the button within LW's firewall config? Did you set up a static IP address first? If not, your port forwarding won't work. There are very good instructions below
http://www.portforward.com/english/r...2/Limewire.htm

If your ISP's traffic shaping, it doesn't necessarily mean that you can't connect... means that your bandwidth will be shaped & so your download speed will suffer but many people are still able to connect ok. Try going through the portforward.com instructions (if you already haven't) & just choose a higher port instead of the default 6346 (even though it's not blocked). Going to a higher port is about the only thing that may make a difference if an ISP's shaping. You could check with Atlantic & find out whether they only apply shaping at certain times... some ISPs only do this during their "peak" hours.