What you're reporting is a different issue from JBAS-2439, although very similar. This is the first report I've seen of it; perhaps the similarity in description to JBAS-2439 led people to not report it.
If I can verify it it will be fixed in 4.0.4 FINAL.
Did you see an error in the logs of your other server, perhaps related to invoking DistributedReplicantManagerImpl.lookupLocalReplicants()? The only way I see to get a ClassCastException at the line indicated is if the remote node threw an exception.
I found that the problem was with concurrent.jar, I had replaced the original concurrent.jar with a different version which caused the exception.
With the bundled concurrent.jar all is well.