I have two SP lists:


I have a screen that adds a record to the 'Time Sheet' list.

On this form, I have added drop downs from the 'Admin Role' list and cannot save a record on the 'Time Sheet'. It gives me an error of "The requested operation is invalid. server respond: list failed: object must implement IConvertible" for submitting the form.
Does anyone know how to add a record to a list using drop downs from another list? All the fields are text except for date and hours