Unity version?
Does dbWalker cough up any errors on this guy? I'm assuming it's a delivery location on the local Unity server and not one that's replicated from another Unity box, right? You're not supposed to be able to open those...
that error message would lead me to believe that the location object Id reference on that object can't be resolved in the location table - something the updated version of dbWalker should bark about. Be sure to fetch the latest version of dbWalker on its home page here:
http://www.ciscounitytools.com/App_DirectoryWalker4.htm