use remote interface successful, but use local interface fai

[xzs2008]

I devolep a EJB use jboss 4.05 .

use romote interface success.

edm = (EdmService) ctx.lookup("EdmService/remote");
Employee employee = edm.Login("xzs","123"); // ok

but use local interface failed!
edm = (EdmService) ctx.lookup("EdmService/local");
Employee employee = edm.Login("xzs","123"); // failed

error info:
java.lang.ClassCastException: com.byd.edm.domain.Employee
08:59:00,843 ERROR [STDERR] at $Proxy112.Login(Unknown Source)