Hi,
I've had a look at the plugin, and it seems highly customized for your website. Is this a plugin that you have created yourself? I would suggest contacting the programmer who originally built it and asking them if they know what could be causing the problem.
If you would like us to have a look into what could be causing the issue you can send an e-mail to consulting@interactivetools.com.
Thanks!
Greg
Greg Thomas
PHP Programmer - interactivetools.com