Confused with IcePack demos

Ice Version:2.1.2

first I add hello demo

icepackadmin --Ice.Config=config -e "application add 'application.xml'"

then I add simple demo according the READMEs.
The hello demo runs OK,but when I run simple demo's client,it report

./client: invalid proxy

or

LocatorInfo.cpp:330: Ice::NotRegisteredException:
 no object adapter with id `IceBox1.Service1.Hello' is registered

when I add some codes in Client.cpp

Ice::PropertiesPtr properties = communicator->getProperties();

    IcePack::QueryPrx query = IcePack::QueryPrx::checkedCast(communicator->stringToProxy("IcePack/Query"));

    Ice::ObjectPrx base = query->findObjectByType("::Demo::Hello");
    cout << base->ice_id() << endl;  //added code
...

I got ": : Demo::HelloFactory" :eek:
I think maybe the hello demo's slice defination : : Demo::Hello class is incompatible with the simple demo's : : Demo::Hello interface. So I remove the
hello demo's application with icepackadmin's "application remove" instruction.But when I back to the simple demo's client,I just got the same output. I even use dumpdb to see the db/registry/objectregistry and found nothing about HelloFactory. So why?

Are you trying to run the simple client against the hello server? If so, you cannot do that. The simple client runs against the simple server, and the hello client against the hello server.