You are trying to re-submit the same post error message

Hello, all. I must be doing something stupid as I have not found anyone else having this error. Whenever anyone adds a comment to a blog post on our http://www.spiritualoutreach.com site they receive the following error message in bold red letters:

"You are trying to re-submit the same post. You have probably clicked the submit button more than once."

Any idea what is causing this? I am using MODx 0.9.6 with Jot 1.1.2. Here is my snippet call and page set up:

<h1>[*pagetitle*]</h1>
[*content*]
<p>&nbsp;</p>
[!Jot? &subscribe=`1` &moderated=`1` &pagination=`10` &canpost=`coworkers` &placeholders=`1` &output=`0` &canmoderate=`moderators` !]
[+jot.html.navigation+]
[+jot.html.comments+]
[+jot.html.moderate+]
[+jot.html.form+]
[!Personalize? &yesChunk=`Empty` &noChunk=`MustLoginToComment` !]

Thanks muchly - John