Hi minht,
That blog post does reference Toad Data Point. Are you trying to use Toad Data Point in your environment or Toad for Oracle? If TDP, you may need to post questions about that to the Toad Data Point forum, located here:
http://www.toadworld.com/products/toad-data-point/f/36
Either way, you can always edit your TNSNames file using Toad for Oracle by downloading the trial and clicking on the "TNSNames Editor" button on Toad's Login window, located here:
That will let you edit your TNSNames file and place it in the correct place.
-John