Just to be sure that we are talking about the same things:
You copied and adjusted the bracket-style example configuration from this thread (or from the sogo manual; same same ...) into
This is the file used by the SOGo daemon by default. It should be owned by the sogo user. The first time you use the defaults command on that file, the file should get automagically converted to the new xml format.
Alternatively you can build up the file using the defaults write command (very important: as user sogo), as described in the SOGo manual straight away. I just find it easier to adjust all the ldap and database details in a text file.
SOGo should be ready to go now. Could you please confirm that you followed these steps, please. And if so, and SOGo is still not running, could you please post (or attach) your .GNUstepDefaults-file, please.