This information refers to information for Legacy Top Pages in Site Explorer. This section can be found in the bottom section, under Legacy Reports in the Sidebar. There's also a new version of this report. More about the new Top Pages report here.
When you see the above message "There are no results in our index for the specified domain/URL" for a target domain in Site Explorer, it means that our crawler has not found any backlinks for it yet. It is also the case that we have yet to crawl any pages from the domain.
It is also possible that pages having links to this website were considered as having low rating and therefore will not be crawled.
You may recheck in 1 - 2 weeks, as this period is usually enough for us to find and start reporting data.