assigning cost center

Hi Expert

I need you guidance

while doing intial hiring action, i need that the COST center should be defaulted in Organization infotype(IT0001) but its coming blank. i have hired already 4 employees without cost center. now want to assign the costcenter for those employees as well as newly hiring employees

i tried assign through OM that is through O 1001 and subtype A001 and type of related object is given as COST CENTER.

so getting an error saying "ENTRY IS NOT ALLOWED DUE TO K ***** AND P *****

PLEASE GUIDE ME..