* Here's the issue, on log-off, the routine sets up a null useragent member and then tries to save it to the database.. where it was going wrong, is the database had a check to do *nothing* when it got a null useragent. I made it delete the userAgent row. This should be a good enough fix to solve the problem. It still needs to be looked at by a DB guy

OpenSim/Framework/Communications/UserManagerBase.cs

@@ -253,6 +253,7 @@ namespace OpenSim.Framework.UserManagement
         {
             UserProfileData profile = GetUserProfile(agentID);
             profile.currentAgent = null;
+            
             setUserProfile(profile);
         }