Before we can open ports for BearShare, we need to figure out what ports BearShare is using. Here is a brief walkthrough on how to do that. Go ahead and open up BearShare.
Click Setup in the menu at the top of your screen. In the list that drops down click Connection.
On this page you should see a Listening Port for Incomming TCP and UDP Connections box. This box contains the port you need to open to the computer you are running BearShare on. You can change this port number if you want to. Please enter the port you chose into the box below.
Click the Firewall button near the left hand side of the page.