Message Oracle TNS-01201 - Listener cannot find executable string for SID string

ERRORListener cannot find executable string for SID string
CAUSEThe executable for the Oracle dedicated server process cannot be found.
ACTIONCheck the appropriate SID_DESC in LISTENER.ORA to make sure that the ORACLE_HOME component is pointing to a valid location. If this component is not set, then check the value of the ORACLE_HOME environment variable.