Where to add TNS names.

Use Agent Ransack to search your PC for "tnsnames.ora" as this file should have your TNS names. Edit in Notepad or Notepad++. Add a new entry like so:

MYTNSNAME =
   (DESCRIPTION =
      (ADDRESS_LIST =
         (ADDRESS = (PROTOCOL = TCP)(HOST = FOO)(PORT = 1521))
      )
      (CONNECT_DATA =
         (SERVICE_NAME = VIS)
      )
   )