I'm not sure what happened but I was doing a test checkout on my cart and went to go redeem a gift certificate and the amount was actually added to the total instead of subtracted. Can anyone help me with this?

So far I have added the ZenApple templete along with a columar mod for my product listings. I also rearrange the code for the product details page but haven't touched anything for gift certificates and I don't even know where to look to try to correct this.