One thing I need to mention is that when a coupon code is NOT applied, it works fine and goes through the Paypal checkout process from what I can tell since I haven't gone all the way with the payment process through paypal... If I use it in sandbox mode it gives me the error...

2013-11-05 20:57:56 - App Warning:  AbanteCart core v.1.1.7 PayPal Express Checkout Error: Security header is not valid. Test mode = 1. in /extensions/paypal_express_checkout/storefront/controller/responses/extension/paypal_express_checkout.php on line 228