INCAR file

Dear Users and experts
I have simple question for some compound say SmCo5
I downloaded the file SmCo5 MPRelaxSet from your site which contain The INCAR ,KPOINTS and POSCAR I put POTCAR from licensed Vasp as in the wiki direction
to simulate DOS and band structure. To get the same DOS & Band as it is in your site.
I am getting errors and sometimes advice to change INCAR parameter
My question is do I have to change any parameter of the 3 downloaded files.?
Please I need your advise to go in the right track to learn how to manage simulation of similar compound.
Thank you very much for your help