Problem with matchcode for my select-options in selection screen

Hi guys,

I used this for my selection screen...

SELECT-OPTIONS: s_arbpl FOR crhd-arbpl OBLIGATORY.

SELECT-OPTIONS: s_matnr FOR mseg-matnr.

SELECT-OPTIONS: s_dates FOR crhd-begda OBLIGATORY.

but there is no match code s_arbpl while other have?

what would be the reason for this? Thanks a lot!

Rgds,

Mark