First start your player and delete all the wrong boxes while logged into your Sling Account.
Then assuming you are running Windows XP. Put a copy of the file, not the original one in case there is a problem, into your C:\Documents and Settings\All Users\Application Data\Sling Media\SlingPlayer\2.0 folder.
While on LAN start 2.0.4.x player and log into your sling account. You should see all the Slingboxes. Connect to each one for a bit and then go to the next. That should save the new boxes to Sling Accounts.