Hi,
Please do to the following steps :
1. Go to SE16
2. Enter table name as TBRG
3. Click on Create
4. Enter Object F_BKPF_BLA
5. Enter Value - this will be yours authorization object value.
6. Enter Description
7. Save
8. Go to transaction code PFCG
9. Create a new role
10. Click on 
11. Enter Object F_BKPF_BLA
12. Enter Value - this value is the value created by you in table TBRG.
13. Enter Activities
14. Generate 
.
15. Assign role to users.
Please remove authorization object F_BKPF_BLA from all the existing roles before assigning newly created role to users.
We hope your problem gets resolved by following this steps else revert.
Regards,
Tejas