Trouble setting up private server

Hello,
I am having problems setting up a private server properly. I've forwarded Port 17171 to my PC in my router settings. If i leave the serverAddress field at "0.0.0.0" in the config.xml file, the server will start without error messages, but friends can't seem to connect to my server. They get an error along the lines of "Unable to connect to server: X" where X stands for the computername, indicating that at least there is some kind of communication. If on the other hand i set serverAddress to my external IP address as proposed in the FAQ, the server console displays an error message:
"FATAL [2013-03-06 21:04 [18:088]] Main[main]: Failed to start server - xxx.xxx.xxx.xxx:17171/?serializationtype=jboss
java.io.IOException: SocketServerInvoker[xxx.xxx.xxx.xxx:17171] error creating ServerSocket[xxx.xxx.xxx.xxx:17171]: Cannot assign requested address: JVM_Bind
at org.jboss.remoting.transport.socket.SocketServerInvoker.createServerSockets(SocketServerInvoker.java:375)
at org.jboss.remoting.transport.socket.SocketServerInvoker.start(SocketServerInvoker.java:251)
at org.jboss.remoting.transport.bisocket.BisocketServerInvoker.start(BisocketServerInvoker.java:193)
at org.jboss.remoting.transport.Connector.start(Connector.java:376)
at org.jboss.remoting.transporter.TransporterServer.start(TransporterServer.java:198)
at mage.server.Main.main(Main.java:118)"
where xxx.xxx.xxx.xxx stands for my external IP.
The port is definitely not in use by anything else. Also i've tried this on Win7 64-bit with Java 7 as well as Ubuntu 32-bit with Java 6 and Java 7.
If anyone has an idea what might be going wrong here let me know.
Thanks in advance,
Cereal
I am having problems setting up a private server properly. I've forwarded Port 17171 to my PC in my router settings. If i leave the serverAddress field at "0.0.0.0" in the config.xml file, the server will start without error messages, but friends can't seem to connect to my server. They get an error along the lines of "Unable to connect to server: X" where X stands for the computername, indicating that at least there is some kind of communication. If on the other hand i set serverAddress to my external IP address as proposed in the FAQ, the server console displays an error message:
"FATAL [2013-03-06 21:04 [18:088]] Main[main]: Failed to start server - xxx.xxx.xxx.xxx:17171/?serializationtype=jboss
java.io.IOException: SocketServerInvoker[xxx.xxx.xxx.xxx:17171] error creating ServerSocket[xxx.xxx.xxx.xxx:17171]: Cannot assign requested address: JVM_Bind
at org.jboss.remoting.transport.socket.SocketServerInvoker.createServerSockets(SocketServerInvoker.java:375)
at org.jboss.remoting.transport.socket.SocketServerInvoker.start(SocketServerInvoker.java:251)
at org.jboss.remoting.transport.bisocket.BisocketServerInvoker.start(BisocketServerInvoker.java:193)
at org.jboss.remoting.transport.Connector.start(Connector.java:376)
at org.jboss.remoting.transporter.TransporterServer.start(TransporterServer.java:198)
at mage.server.Main.main(Main.java:118)"
where xxx.xxx.xxx.xxx stands for my external IP.
The port is definitely not in use by anything else. Also i've tried this on Win7 64-bit with Java 7 as well as Ubuntu 32-bit with Java 6 and Java 7.
If anyone has an idea what might be going wrong here let me know.
Thanks in advance,
Cereal