- Are you able to do scanning without active scanning using lsclient?
- The database connection and permission seems ok.
- What is your network setup (windows 2003 forest?, ...)
From what I can find this is an error connecting to one of the global catalog servers.
http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=979661) make sure that you have the latest servicepacks of the dotnet framework. (windows update should do the trick)
2) do a "dcdiag /e /q" on your forest to make sure that active directory is working properly.