I am trying to upgrade from 11 to 11.1. I have already converted the SQl 2005 db to SQl 2008 R2 but cannot get past the "information gathering stage" during the upgrade. I get the following error:

Unable to contact domain at whatever.domain.local. Please make sure DNS is setup, the server is reachable and the specified domain is valid.

I know there is no problem with DNS or the domain.

Does anyone know what the problem could be and how to troubleshoot this?