Can’t launch glassfish on ec2 – can’t open port

I'm trying to start glassfish on an EBS-based AMI of Ubuntu 10.04 64-bit. I have used glassfish on non-ec2 servers with no problems, but on ec2 I get this message:

$ sudo -u glassfish bin/asadmin start-domain domain1
There is a process already using the admin port 4848 -- it probably is another instance of a GlassFish server.
Command start-domain failed.

I know that ec2 has requires that firewall rules be modified using ec2-authorize to let outside traffic thru the firewall, as I had to do to make ssh work. This still doesn't explain the port error when all I'm trying to do is start glassfish so I can try

$ wget localhost:8080

and make sure it's working.

This is very frustrating and I'd really appreciate any help.

Thanks.

FINAL UPDATE:
Sorry if you came here looking for answers. I never figured out what was causing the problem. I created another fresh instance, installed the same stuff, and Glassfish worked perfectly. Something obviously got boned during installation, but I have no idea what. I guess it will remain a mystery.

UPDATE:
Here's what I get from netstat:

# netstat -nuptl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      462/sshd        
tcp6       0      0 :::22                   :::*                    LISTEN      462/sshd        
udp        0      0 0.0.0.0:5353            0.0.0.0:*                           483/avahi-daemon: r
udp        0      0 0.0.0.0:1194            0.0.0.0:*                           589/openvpn     
udp        0      0 0.0.0.0:37940           0.0.0.0:*                           483/avahi-daemon: r
udp        0      0 0.0.0.0:68              0.0.0.0:*                           377/dhclient3   

UPDATE: One more thing…
I know that the "net.ipv6.bindv6only" kernel option can cause problems with java networking, so I did set this:

# sysctl -w net.ipv6.bindv6only=0

UPDATE: I also verified that it has nothing at all to do with the port number (4848). As you can see here, when I changed the admin-listener port in domain.xml to 4949, I get a similar message:

# sudo -u glassfish bin/asadmin start-domain domain1
There is a process already using the admin port 4949 -- it probably is another instance of a GlassFish server.
Command start-domain failed.

UPDATE:
Here are the contents of /etc/hosts:

127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

I should mention that I have another Ubuntu Lucid 10.04 64-bit slice that is NOT hosted on ec2, and set it up the exact same way with no problems whatsoever.

Also server.log doesn't offer much insight either:

# cat ./server.log 
Nov 20, 2010 8:46:49 AM com.sun.enterprise.admin.launcher.GFLauncherLogger info
INFO: JVM invocation command line:
/usr/lib/jvm/java-6-sun-1.6.0.22/bin/java
-cp
/opt/glassfishv3/glassfish/modules/glassfish.jar
-XX:+UnlockDiagnosticVMOptions
-XX:MaxPermSize=192m
-XX:NewRatio=2
-XX:+LogVMOutput
-XX:LogFile=/opt/glassfishv3/glassfish/domains/domain1/logs/jvm.log
-Xmx512m
-client
-javaagent:/opt/glassfishv3/glassfish/lib/monitor/btrace-agent.jar=unsafe=true,noServer=true
-Dosgi.shell.telnet.maxconn=1
-Djdbc.drivers=org.apache.derby.jdbc.ClientDriver
-Dfelix.fileinstall.dir=/opt/glassfishv3/glassfish/modules/autostart/
-Djavax.net.ssl.keyStore=/opt/glassfishv3/glassfish/domains/domain1/config/keystore.jks
-Dosgi.shell.telnet.port=6666
-Djava.security.policy=/opt/glassfishv3/glassfish/domains/domain1/config/server.policy
-Dfelix.fileinstall.poll=5000
-Dcom.sun.aas.instanceRoot=/opt/glassfishv3/glassfish/domains/domain1
-Dcom.sun.enterprise.config.config_environment_factory_class=com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory
-Dosgi.shell.telnet.ip=127.0.0.1
-Djava.endorsed.dirs=/opt/glassfishv3/glassfish/modules/endorsed:/opt/glassfishv3/glassfish/lib/endorsed
-Dcom.sun.aas.installRoot=/opt/glassfishv3/glassfish
-Djava.ext.dirs=/usr/lib/jvm/java-6-sun-1.6.0.22/lib/ext:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/ext:/opt/glassfishv3/glassfish/domains/domain1/lib/ext
-Dfelix.fileinstall.bundles.new.start=true
-Djavax.net.ssl.trustStore=/opt/glassfishv3/glassfish/domains/domain1/config/cacerts.jks
-Dcom.sun.enterprise.security.httpsOutboundKeyAlias=s1as
-Djava.security.auth.login.config=/opt/glassfishv3/glassfish/domains/domain1/config/login.conf
-DANTLR_USE_DIRECT_CLASS_LOADING=true
-Dfelix.fileinstall.debug=1
-Dorg.glassfish.web.rfc2109_cookie_names_enforced=false
-Djava.library.path=/opt/glassfishv3/glassfish/lib:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64/server:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64:/usr/lib/jvm/java-6-sun-1.6.0.22/lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
com.sun.enterprise.glassfish.bootstrap.ASMain
-domainname
domain1
-asadmin-args
start-domain,,,domain1
-instancename
server
-verbose
false
-debug
false
-asadmin-classpath
/opt/glassfishv3/glassfish/modules/admin-cli.jar
-asadmin-classname
com.sun.enterprise.admin.cli.AsadminMain
-upgrade
false
-domaindir
/opt/glassfishv3/glassfish/domains/domain1
-read-stdin
true