At the port forwarding site, click on LimeWire in the programs list.

Providing your Norton firewall's configured properly, the firewall that LW's detecting is either coming from your modem or (not too sure about this but it may be a possibility) from some firewall associated with the apartment's internet setup. Have you tried using any other p2p apps? If so, could you connect?

If your port 6346 test doesn't work, means LW's default port is blocked. Try changing LW's listening port to something higher (say 64049). Tools > options > advanced > firewall config will bring you to the page. Change the listening port there. You'll also need to change port numbers allowed through your software firewall and any port numbers forwarded through a modem/router. All port numbers used must be the same

If you're going to set up port forwarding, make sure to set up a static IP address first or p/f won't work. You'll find a link for this within the port forwarding guide for your modem.