ora-12560

 Test platform: Windows Server 2008 x64;  Oracle Windows x64

Problem: I can start sqlplus and run from windows but when I start sqlplus from a dos cmd prompt I get an ora-12560 TNS protocol adapter error. What am I doing wrong?

tnsnames.ora

RMS10LIO =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = <host_name>)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = <service_name>)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

listener.ora

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\product\10.2.0\db_1)
      (PROGRAM = extproc)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =