How do I airport-utils to configure my Airport Extreme?
This is probably due to a non-supported java version. I got the same result until I used gcj-4.4. Install command:
apt-get install gcj-4.4-jre gcj-4.4-jdk fastjar
You will then need to use that version of java (i.e. launch with /usr/lib/jvm/java-gcj-4.4/bin/java instead of just java by setting $JAVACMD.)