Account creation problem

Sir in tcode MB31 i am getting following message:-

Create account 50200000 for 18.10.2008 as a cost element in controlling area ARP

Message no. KI280

Diagnosis

Account 50200000 is a profit and loss account. You assigned it to an object in cost accounting (for example, a cost center, order, or project).

System response

Account 50200000 in the determined controlling area ARP must exist as a cost element on the posting date 18.10.2008.

Procedure

u2022 Create account 50200000 as a cost element and then repeat your posting.

u2022 Or, delete auxiliary account assignment to objects in cost accounting.

Can u please suggest me what to do in such case?

Iwait online.