I'm not sure that it will work with 4.0.3. JBoss has made some significant changes from 4.0.2 -> 4.0.3. Give it a go with 4.0.2.
Eeeenteresting... can you give a bit more log (you can email to acoliver ot jboss dat org if you like)? Also if you wanted you could also build from the HEAD which does work in 4.0.3 (or wait until Monday for M4-pre1).
Verify you ear-deployer.xml for isolation ear:
attribute name="Isolated" false attribute
attribute name="CallByValue" false attribute