Is this a bug, or not yet enabled?

In admin, on validate links page, I click on "Duplicate Check"
It just returns me to the admin with the menu and help showing.
The link that is showing at the top is:
admin.cgi?db=Links&view_records=1&URL=http://www.somedomain.com

Except "www.somedomain.com" is the domain I am trying to check.
This happens on url's that are, and are not already in the db.

Chris