I downloaded JBoss Application Server 5 and successfully deployed a war file. I copypasted the Hello.war which has a simple index.jsp file into
\\jboss-5.1.
Actually, for the latest JBOSS 7 AS, we need a .dodeploy marker even for archives. So add a marker to trigger the deployment.
.dodeploy
In my case, I added a Hello.war.deployed file in the same directory and then everything worked fine.
Hello.war.deployed
Hope this helps someone!