It's not normal to have the exact same configuration and jboss not working in the second case, without any error message logged.
Have you tried to re-install your jboss instance (basically just unzip the distribution) and re-deploy your application?
You may also try to upgrade to a newer version (e.g. 3.2.5).
Also check your ports (e.g. netstat -b, from the command line) in case 8080 is used by another process.