simple logic problem in authorization object

hi friends,

below is the code, i am working on authorization object.

i dont know why, for all the comp codes i enter it is

giving the same,

answer not authorized. it is not that the compcode

i am entering is not authorized, if i change the <> to = ,

then it is giving unrestricted data,

whether authorized or not authorized.

AUTHORITY-CHECK OBJECT 'F_BKPF_BUK'

ID 'ACTVT' DUMMY

ID 'BUKRS' FIELD P_FS.

IF SY-SUBRC <> 0.

ZZ_EXIT_BUKRS = 'Y'.

ENDIF.

IF ZZ_EXIT_BUKRS EQ 'Y' .

MESSAGE E999(ZI) WITH 'NO AUTHORITY TO EXECUTE PROGRAM.....!!!'.

ENDIF.

can some one help.

thanks