Zoho creator intermitent form submission error

Zoho creator intermitent form submission error

I have a form that I have created for perspective employees to fill out.  60% of the time, I have no problem with submissions.  However, the rest of the time, people are reporting a pop up submission error when they submit the form.  I have not been able to replicate the error myself, but I am loosing applicants as they are getting frustrated.  Any ideas?  

here is a link to the form:

http://www.crossbarx.org/index.cfm/fa/category.display/category_id/73/JobApp