Hi Ajeh!

PHP is 4.3.11 (Zend 1.3.0) and ZenCart 1.3.6. It was an upgrade from 1.3.5 and was upgraded as is recommended in the upgrade FAQ. But, I've got a bunch of mods installed at this point: Image Handler, Newsletter Only, Email Address Exporter, CrossSell, Attributes Controller, User Tracking, and Singapore Gallery. I'm using the override system as far as I know...

I switched to the Classic template and got the same error when I clicked the "Continue Checkout" button on Step 2 of 3 - Payment Information. It sent me back to the same page (Step 2 of 3) with the error at the top of the page. We've only sold 2 gift certificates prior to this, and I *think* both went through ok. This is the first time I've heard of this problem... Thanks for any help!