Cannot add server in existing deployment: Requested value 'Geo' was not found.

Hello,

we have two healthy CRM 2011 UR13 server on an SQL2008R2 cluster back-end.

When attempting to install 3rd server, we had to bypass key and db version checks with registry entry  decribed in the famous MSDN blog entry.

Install fails with

11:28:48|   Info| Executing Install action: Microsoft.Crm.Setup.Server.AddServerAction
11:28:48|  Error| System.Exception: Action Microsoft.Crm.Setup.Server.AddServerAction failed. ---> System.ArgumentException: Requested value 'Geo' was not found.    at System.Enum.TryParseEnum(Type enumType, String value, Boolean ignoreCase, EnumResult& parseResult)    at System.Enum.Parse(Type enumType, String value, Boolean ignoreCase)  

Same result with a MSDN and a Volume distribution; both are a release level 5.0.9688.583

The 2 installed servers are at 5.0.9690.3448

How can I complete setup?

Thanks in advance for any help.

Patrice Mariet