error while updating a form in Zoho creator

error while updating a form in Zoho creator

 I have set up a new application by uploading the info from a spreadsheet and entering more fields in form view.
Somehow when i update the data it gives me an error message. I have set the new and old fields to accomodate the original settings of the fields given (number / drop down etc

java.lang.String cannot be cast to java.lang.Long