Vista Tutorial - Durable Service persistance failure

I am trying to get a Durable Service to work.

The client reports a fault "An error occured during create" when calling the
service operation marked as [DurableOperation(CanCreateInstance = true)] but
debugging the server shows no errors.

Tracing the SQL Server shows the ".Net SqlClient Data Provider" logging on
when the service starts but no SQL statements been run.

The client is using wsHttpContextBinding and both the client and server are
on the same machine which is running Vista.

Removing the durable service attributes enables the client to communicate
with the service without error.

Any ideas on how to obtain more information on the problem or possible
causes?