Scheduling agreement pricing

Hi,

Pls tell me how the system will pick pricing in scheduling agreement. When i going to header condition system will give me message "

Not possible to determine a condition type

Message no. 06658

Diagnosis

The system was not able to find a condition type for the item. Price determination is therefore not possible.

Procedure

Contact your system administrator.

The latter can maintain the calculation schema assigned to the purchasing document using the Implementation Guide (IMG): Define calculation schema

Pls tell me how i can enter the header level conditions like freight & discounts.

Regards,

Dinesh