Oracle Message PGA-21013 - missing period(.) in fully-qualified local LU name

ERRORmissing period(.) in fully-qualified local LU name
CAUSEThere is no period (.) in the fully-qualified local LU name specified as the first argument to the pg4arrm program.
ACTIONA fully-qualified local LU name must contain a network name and an LU name, separated by a period (.). Reenter the command line with a valid fully-qualified local LU name specified.