You will still be auto fail because you have changed the given interface DB, from not extending anything to extending another interface.
I wonder, why you need to throw RemoteException for the data access. It is because it is only focus on data access no matter you are local or remote client. Also, as this is a low level API that access with the "DB", should the client really being able to invoke it directly?
For my implementation, I keep everything unchanged for the DB access interface, while I will provide (create) another interface for the user (GUI) to invoke with the network server, and only the network server (or data server) will invoke the DB interface.