That last statement is correct, shared libs in an EAR go into EAR/lib/ in Java EE 5.0. However, in J2EE 1.4 and JBoss 4.0, you need to use a MANIFEST.MF in the ejb.jar and web.war archives, and reference the shared library by name in a Classpath: entry. Make sure that you have a new line after this, and that there is something in that new line (like a Created-By: entry). This is totally broken stuff in J2EE 1.4. I've lost a lot of hair until I figured that one out. The way most Seam examples declare shared JARs in an EAR now, via a client module in application.xml, is not really correct and slower (these JARs are scanned by deployers), but seems to work. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3995733#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...