Just tested this myself.
I did the following and it worked fine:
1) Click the add button
2) Type in the ip address of the DNS
3) Hit the Enter key
I tried this on the same version of Ubuntu as you and on both my wireless and wired connections.
When you open the Network Manager, it is asking you to authenticate right?
EDIT: I checked the wording in my interface and it says "Type address", but yours says "type your ip"?
I'm opening this application by going to System > Administration > Network. Are you doing the same?
Last edited by thebouv; 08-14-2007 at 03:11 PM.