Can't Resolve a Error Message

When i click save on a form application. I get an error message. “: must have at most 20 characters”.

The only field required is the invoice number. Which is auto generated by the database or onUpdate uses the existing variable.

How can I debug the error message. Even tried turning on the debug option in the form application. Can’t seem to locate the issue.

See attached screenshot.

Screen Shot 2013-12-14 at 9.45.05 AM.jpg

Just check the input fields. Most likely that you field length is different from the database length. You can solve issues like these in the field menu.