Firewall not allowing people to join my server, even though I allowed it?

I'm using "Comodo Firewall" (might not sound familiar to some of you, but it is a very good one.)

When someone tried to connect to my server I got a notification that the craftbukkit.jar wants to connect to the internet. I allowed that request, but those people are telling me they're getting "Can't reach server" on their Minecraft screen.
So that probably means my firewall is blocking the connection.

Can somebody please help me? I can't seem to find a solution by changing things in the firewall options and it is freaking me out!

I have java 64 bit and I have craftbukkit build 1337



Note: I'm using Hamachi to port-forward, so using the port 25565 is NOT an option to solve my problem.
Note2: I had a server before on an old PC. Now I have a new one and I converted the worlds and plugins from the old PC to this one, nothing else.
On that old PC, I also had Comodo Firewall, so maybe it isn't the firewall... Maybe it's the Windows firewall..

Help?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.