Hello @SteveBrewer,
In the diagnostic log the message "String or binary data would be truncated. The statement has been terminated." typically indicates that a value for a field exceeds the field length defined in the field. For example, if the field length for a text field is 5 and the value "Bananas" is submitted that would run into this message.
Another thing to check is if you are using a submission_url in your survey check if any fields are set to non nullable and ensure the corresponding question in your XLSForm is submitting a value.
Thank you,
Zach
