What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Kindly try embedding your form using the iframe method, this will help prevent script conflicts between the form and your site. http://www.jotform.com/help/148-Getting-the-Form-iFrame-Code
I tested the direct link of the form and the submissions goes through, I'm redirected to the PayPal site since you have a product payment widget for PayPal on your form.