I am seeing the same issue. I tried ESB-4.7 and 4.8 and see the same error.
(The quickstart/helloworld sendesb works when run from server...but fails when run remotely from eclipse.)
I have seen other posts indicating a similar problem - fixes typically indicate a bad classpath.
However, when I duplicate posted classpaths, it still does not work.
Any help/insight appreciated.
Server: Linux, jboss-6.0.0.20100216-M2, ESB-4.7
Client: XP, Galileo