CI871 Profinet Communication won't Start

We are trying to start up a new Profinet Network using 2*PM891, 2*CI871 and 5*Phoenix Axioline F IO Stations.

We have set the IP addresses in the Axioline Stations, Configured the Bus Layout in the PM891 to match the installed IO Stations and Modules and tried to start the network.

No I/O stations will start. All show an error in control builder "Waiting for Hardware Configuration"

The Web Interface shows that the CI871 modules are connected to the bus and all of the IO stations appear in the live list with their correct module names, IP, subnet, gateway and MAC Addresses.

I've even read the manuals ( twice ) and still cant see what we're doing wrong...

Any ideas ?