environment: sles 10 sp3, oes2, cluster services

problem: reconfiguring oes to add a node to the cluster is causing the error „failed to add node to cluster

history: I installed a 4 node cluster in a HP C7000 blade. We had to replace the network switch in the blade center by a virtual connect flex-10. This resulted in a loss of network connectivity, so I removed 3 of 4 nodes from cluster and eDirectory.
This worked fine, replication and time synchronisation was succesfully and all server objects belonging to these 3 servers were deleted.

Now the new switch has been configured and network connection reestablished. Reconfiguring eDirectory and other oes2 services succeeds, alle server objects are recreated, eDirectory is in sync, but reconfiguring cluster services does not succeed.

What do I have to do, to reconfigure cluster service and add nodes to the cluster?

Thank you for all hints.