diff -r -u PortableServer.orig/Servant_Upcall.cpp PortableServer/Servant_Upcall.cpp
--- PortableServer.orig/Servant_Upcall.cpp	2006-02-13 04:23:52.000000000 +0100
+++ PortableServer/Servant_Upcall.cpp	2006-04-21 11:00:18.480507500 +0200
@@ -288,7 +288,10 @@
           // Cleanup servant locator related state.  Note that because
           // this operation does not change any Object Adapter related
           // state, it is ok to call it outside the lock.
-          this->post_invoke_servant_cleanup ();
+          if ( this->operation() && this->servant() )
+          {
+            this->post_invoke_servant_cleanup ();
+          }
 
           // Since the object adapter lock was released, we must acquire
           // it.