Then something is blocking Limewire from seeing your IP i.e. a firewall.

Pretty much, if you have a brickwall in from of the blue Earth you will have trouble direct connecting.

You can of course find your IP by using e.g. What Is My IP Address? - IP Address Lookup, Info, Speed Test, and more but chances are your friend can't connect to you.

your friend has to insert IP:Port into the Direct Connect tab e.g. 213.64.78.157:6437