incomeing payment with discount

Hi all,

I was doing incomeing payment with discount allowed , here payment terms and discount amt also is correct, but the system did't show in the customer and discound allowed line time , the document did't not saved, the system shows one error.

error :Rules for posting key 15 and out 200200 set incorrectly for SKFBT field

pls can anybody help me

Regards

sri