Our recent change of the consumer site to Windows Live Local broke some of the functionality of the Map Search Control, or Commercial Control. Apparently when we updated the site's URL the redirect to the new URL didn't work for the proxy we wrote, an error that didn't surface in our testing. So, your Commercial Control application probably needs updating. The change is simple but necessary--you must manually update the code for your proxy so it references the new URL:
HttpWebRequest searchRequest = (HttpWebRequest) WebRequest.Create(http://virtualearth.msn.com/search.ashx);
Should be changed to:
HttpWebRequest searchRequest = (HttpWebRequest) WebRequest.Create(http://local.live.com/search.ashx);
The same change applies to the Ads proxy, which should point to http://local.live.com/ads.ashx.
This is definitely something that shouldn't have happened, even for a beta product, without significant notice (or, in an ideal world, never at all). We are working to ensure it doesn't happen again. The documentation on MSDN is being updated now to reflect the changes.