magento checkout error \"undefined\" with paypal advanced

please go to atozappliance.com. select option to log in/create an account. add a product to shopping cart (from a link "Pay for services"), and a $1.00 to test, and go thought the process to checkout, select option for payment "Credit Card" and place the order. Theoretically it should load the iframe with paypal section to enter cc or bill me later buttons, but it is not. it throws the error message as "undefined" I called paypal and all setting are set up correctly, and the option for paypal express work fine. The problem is with the iframe loading on the page... need help. **Important: please read/see the error first before bidding. Thank you, looking forward to work with you