2 problems:
1) For file upload to function, the forms encoding type needs to be change to multipart/form data.
in design view, select the first form element, then in the tag selector select the form tag to view the form properties in the property inspector and change the encoding type.
2) open the server behaviors panel and double click the Insert Record server behavior to edit it. in the insert record behavior, select the URL field, and change the binding to use the Uploaded Files (url) -> Server File Name binding.