Entry does not exist in TVKWZ (check entry) vbak-vkbur

I have created a module pool screen where i inserted a field for sales office with data dictionary vbak-vkbur, but when i enter its value on execute, it throws error as Entry does not exist in TVKWZ (check entry). However all the configurations are properly maintained for sales office and I do able to created the SO with the same sales office with VA01. Entry also exists in table TVKWZ with all required combinations, but still i do not why this error occurs in my module screen.