Hi Luis,
It looks like you have a different problem, since you're talking about multiple instances of RemotingClassLoader. It is possible, under some circumstances, for Remoting to create a new RemotingClassLoader for every invocation. Can you tell me which subsystem of AS 6 these RemotingClassLoaders are associated with?
re: "Is there any Classloader issue with Remoting 3?"
I'm not vey familiar with Remoting 3. However, I can tell you that it was written by David Lloyd, who know a LOT about classloading.
-Ron