InfoPath Dev

Hi - hoping someone can help me - I am sure this should be straighforward but it is proving to be a headache. I am using InfoPath 2003 SP3. I have a form with a repeating section within which is a dropdown list (populated from a secondary data source) from which a user selects the name of a property...

Thanks. Its actually kinda challenging for me live by it. The default of ZeroValue in the old form was 0. In this new form, I tried 0 and other values like 2. In this unique case, using code is not an option due to various legitimate reasons. But I found a solution! I needed a global sum element/attribute...