Credit Card authorization problem

I have a UK webstore that is set up to take payments through PayPal Website Payments Pro UK. We take credit card payment or PayPal payment. Recently we have not been receiving payments through credit cards and after some testing realised there was a problem when someone wanted to pay with credit card, they would be redirected to the payment failed page.

I have examined the confirm.asp page and in particular the eCart Local Checkout server behavior. I noticed on step 5 'Use PayPal Express Checkout' is unchecked. I was on the understanding that Express Checkout was the credit card payments part.

Would I need to fill in this section in order to get the credit card payments working again? If this is the fault I have no idea what may have changed this to revert back to it's inactive state.

One further question, if someone wishes to pay by debit card then they usually would need to provide a card start date or issue number. I cannot see where this is added to my website.

Hope you can help

Many thanks

Kelly