by the way i am using jboss 2.2 with embedded tomcat 3.2
I'm using serializable value objects without any problems on JBoss 2.4. Is your exception being thrown on the server or the client ?
seems like it is on the client side..my client is a jsp page.
and i see the error on the client side.
I had all sorts of problems with value objects when I switched to JBoss (using RMI) from a IIOP based app server (which seems to be more forgiving of unused class references). It turned out that RMI is just much more sensitive and each layer must have any class referred to (or by a super classes) by any interface along the way. So even classes that the client didn't use would blow things up! The error messages would appear very confusing as a result. By including every class that might be required by RMI the problem just went away. I don't know enough about your setup to know if this really helps though.