When trying to run the examples shipped in Seam 1.2.1.GA with AS 4.2.1.GA I had to add to the root file in the jboss-seam-1.2.1.GA directory in the build.properties file two additional lines to get this to deploy to my app server:
jboss.ejb3.home = /home/jtyrrell/servers/jboss-4.2.1.GA
jboss.ejb3.config = default

Why was jboss.home not enough and why did i have to add these other entries to deploy the example applications?