Hi,
Can you open the server.log in \jbpm-installer\jboss-as-7.0.2.Final\standalone\log\server.log ?
Hopefully there are some entry that helps to figure out why the JBOSS AS 7 fails to start.
Maybe its a good idea to delete all the content of server.log and then retry the "ant start.demo.noeclipse"
to get a cleaner server.log
Regards,
Thomas Setiabudi