What is this class:
de.ovsag.profiler.proxies.ProxyStateless is only a client side wrapper for the Stateless Session bean, this basically maps down to:
This is some form of lookup problem in the clustered environment.
JNDI checked via jmx-console is ok, as far as I can tell.
Running the app on the server to eliminate routing issues yields the same error...
the same applies for a windows 2k setup with jboss 3.0.4 and jdk 1.4.1
What happens if you remove the PortableRemoteObject cast and replace it by a direct cast? If it fails as well, send the simplest EJB + client that exhibit this behaviour.