1. I don't have Leopard yet, thought I'd wait till I get my new computer in coming months. But the firewall configuration should be similar to Tiger's; OSX Firewall settings for Tiger, else turn it off. I keep my firewall off whilst using LW.

2. Make sure you're not using same ports as any other program such as BitTorrent.

3. When you say you tried port forwarding, did you ensure you set up a static ip first, as otherwise the port forward process simply won't work unless you do it before setting the firewall port rule, because it's based on ip; PortForward.com - Setting up Static ip for Mac OSX. Also, after changing any router settings, it is a good idea to reboot both router & computer, though not always necessary depending on brand & model.

4. (a) Problems with the search, __ (b) Hostiles List

5. You can go to LW's prefs (keyboard shortcut: ⌘ ,) & under Connections, set LW to start manually. Then restart LW, wait for it to load & settle for a few mins, then go to menu bar, File > Connect. Give it plenty of time to try to connect.

6. Also, do you see a brick wall in front of the blue world icon at the bottom of LW's interface? (sample image)