Currency rate calculation failed. Enter rate NGN / USD rate type M for 2012

Full Error Text

Currency rate calculation failed. Enter rate NGN / USD rate type M for 20120229 in t

Message no. GMMASTERDATA039

This error came while trying to create a Foreign Currency grant. I have been able to work with foreign currency for invoices and it is correctly converted to the company code currency. This error therefore means that I need to maintain the currency conversion rate again for grants. Is this correct? Can anyone help?