PayPal: the page you were looking for wasn't found

[Penn Wooding]

I have recently done away with the SSL certificate in favour of just using PayPal. Basically, I want people to arrive at the PayPal page and either choose PayPal itself, or credit card payment. However, I'm having a few problems setting it up. I have enabled PayPal (PP) in the payment method list. In the PayPal configuration, I have selected credit card. However, if I place an order it just goes to a page saying "page wasn't found" In the checkout section, I have got number three selected, I'm not sure if this is causing my problem.

I obviously need to obtain people's addresses but I'm not sure what's wrong, any help would be appreciated