JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
Are you still having this issue? I test submitted your jotform http://www.jotformpro.com/form/43638111838962 and I was able to still submit more at this time.
From what I checked, you also had posted similar question here http://www.jotform.com/answers/485337 which my colleague had help resolve the issue.
Please inform us if issue still persist at this time.