Kills Coupon Function

Hello, I installed this pluging and it kills coupon functionality on my site. If I activate the plugin and a person enters a coupon code in cart or at checkout the credit card area is greyed out and credit card info cannot be entered. If I de-activate the plugin the coupon function works fine. Any ideas how to fix? The plugin is deactivated right now.

The page I need help with: [log in to see the link]