Can you give us a total desciption of your set up:
1. OS version? (eg: Windows 98)
2. What firewalls you have?
3. How much ram?
4. Hard Disk space available?
5. Connection type? (eg: dialup, broadband, cable, etc.)
6. Modem & router brand name & model numbers?
7. Where are you trying to connect from (home, school, work, etc.)?
8. What version of Limewire (LW) & Java do you have? (Go to LW's menu Help>About LW...) Will show both LW & Java version.
9. Who is your isp provider (Internet Service Provider)?
10. Are you sharing the connection with other computers or p2p sharing programs? If yes, please give details of set up.
11. Which port do you have LW running on? Go to LW's menu bar, Tools>Options>Advanced>Firewalls & see which ports it is using.
These details are vital if you want us to find out what your connection problem is.

Port 80 is a web port. Do you run a web page anywhere? Do you have messenger or any other communication software open? Are you running any other p2p program or video conferencing or gaming program?

BTW are you running in UPnP mode on your router? If yes, then only programs on your computer will open ports that LW has not requested. LW can only request a maximum of 2 ports. Connection & listening for incoming. Most people use the same port for both. Whereas the other programs I hinted above may request multiple ports to be opened!