Well the divide by 0 would be on the right hand of the / so, either estimatedwork and/or custeventcustevent_initial_cost is coming back 0, since you're multiplying them by each other, it would 0 out anything returned. You can do a search and just return those fields ( without any math ) and check. If you have inline editing, you could take care of a lot of them at once, if there are many