Welcome to the forum.
The most likely reason for an UnmarshalOutOfBoundsException is a mismatch between the Slice definitions used by client and server. For example, this can occur if you change your Slice definitions and rebuild the server, but forget to rebuild the client.
This
FAQ provides more information on UnmarshalOutOfBoundsException.
Let us know if you're still having trouble.
Take care,
Mark