authority check

hi!

i wrote authority check for an object.

the problrm is that i get always subrc = 12, eventhough

i have sap all.

this is the code

IF SY-TCODE = 'VA21' OR SY-TCODE = 'VA22' OR SY-TCODE = 'VA23'.

AUTHORITY-CHECK OBJECT 'Z_VBKA_VKD'

ID 'VKBUR' FIELD VBAK-VKBUR.

IF SY-SUBRC NE 0.

MESSAGE E016(ZSD).

ENDIF.

ENDIF.

why am i getting always subrc 12?

what is the syntax for field 'ACTVT'

if the values have to be between 01-04?

thanks

yifat