Planning Area activation error

Hi,

I am trying to setup a new S&OP instance.

Created Planning area, level and key figures.

When i activate the planning area, i am getting the following error

I - Activation Running

E - Check that key figure VSSALESFCST has a calculation defined at the REQUEST level

E - Check that key figure VSSALESFCST in the key figures table has an entry in the key figure calculation definition table

Any pointers will be helpful.

Regards, Vish