[BUG][4.002]Error using Join function with 1 UTM

I have used the join function successfully in SUM 4.002 to tidy up the orphaned devices in the Gateway manager (due to V9 reinstalls, etc.).. but I have one pair that refuse to join. This is the error that I see:

2012:10:18-12:27:20 sum01 accd: 2536170 [0xf37ddb70] ERROR server.user.DeviceTransferGuidCallback null - Transferring 81808972-6562-11DE-9EFA-CBC089C37731 to 635F0658-F786-11E1-9D9A-9198EEC2D6D2 failed: JSON-RPC method/notification 'set_agent_guid' does not exist.
2012:10:18-12:27:22 sum01 accd: 2538385 [0xf17d9b70] ERROR server.user.DeviceTransferGuidCallback null - Transferring 81808972-6562-11DE-9EFA-CBC089C37731 to 635F0658-F786-11E1-9D9A-9198EEC2D6D2 failed: JSON-RPC method/notification 'set_agent_guid' does not exist.