The payment option is selected in checkout.php and there is a browser error: page cannot be not found.
Some payment options use the local orderform page to collect credit card information. See the Payment Gateway Cross Reference page for a list of payment gateways that use "orderform". For security, credit card information must be entered through an encrypted SSL connection. An SSL connection with a valid security certificate must be available and the Secure URL must be set in Shop Parameters > Store Configuration > Advanced Options.