I had to make a manual update to 3.1, and I had all pllugins desabled. After that, it was working good, but was still showing an error message that installation needs to be completed.
Well, I did reactivate the previous plugins, including the wp-domain mapping. Until there it was working good, I could map without problems.
But I decided to run the automatic update to 3.1, to be sure everything is ok. This time the automatic update worked fine. (Of course I had all plugins deactivated ahead).
Now, after reactivating wp-domain mapping, I can no longer map any domains.
I updated this plugin, then removed it, re-installed latest after a fresh download, removed sunrise, re-add sunrise, even changed wp-domain mapping to mu-plugins folder.
Nada, Niente, nor Caliente! it does no longer map :(
Hope you have an idea what to do, besides to start from scratch a 3.1 and re-multisite it.