Error calling EJB methods deployed on WAS 7.0 on remote server (Linux SUSE)

I've two websphere application servers deployed on two different virtual machines (operating system for each one is Linux SUSE). Each server has an enterprise web application deployed on it (the same application is deployed with it's own EJBs and is working properly on it's own). When I configure one web application to lookup and use the EJB on the other server instead of the one deployed on the local server, it is looked up successfully but
when I try to do ejb method invocations (most of methods but not all) I get the following exception:

"java.rmi.MarshalException: CORBA MARSHAL 0x4942f999 No; nested exception is: org.omg.CORBA.MARSHAL: Profile data of length 0x7fffff0a while reading IOR Profile vmcid: IBM minor code: 999 completed: No "

any ideas?

best regards!