OK, I've figured out the source of the problem, but it doesn't make sense.
In the Bizway theme's style.css, is this style:
I created a child theme, simply to change the background color. THis is mt child theme's style.css:
Theme Name: Child of Bizway
Description: Modifies Bizway footer, header background color
Author: Nina Lauderdale
Any thoughts on why this would result in the file upload button not working?