Just aa reminder that NAV/BC Users entering Forum questions are both Users (Functional) and Developers. Users, especially in BC, will not know how to debug and their Partner will need to assist in debugging.
Have you connect with your Partner to debug the message. It will not take long to debug but they will need to assist. It seems the Service Item/Contract has a division error that could be related to the UOM being used in the calc. Check the Service Contract/Item and make sure the QTY and UOM are correct.