什么是一个记录良好的PHP paypal专业课直接付款

Question

I'm in a bit of a rush and dont have much time studying paypals documentation in creating what i need. I have looked at many paypal pro classes for php and they either lack documentation or have classes are very difficult to debug. What i am looking for is direct payment where a user enters their billing address information along with their credit card information and all this is validated on my website without the customer seeing paypal. I am guessing this is what direct payment is called for paypal. Does anyone have a well written, easy to understand and documented paypal pro class. And do i need to be registered with paypal pro in order to accept direct payment?

fyi: this is a custom site so i am not using any 3rd party application/framework.

thanks

ps:

i have tried Angel Eye paypal class (http://www.angelleye.com/paypal-payments-pro-php-class/) and after integrating i get this returned as an error and have no clue what it means

[ERRORS] => Array
        (
            [0] => Array
                (
                    [L_ERRORCODE] => 10002
                    [L_SHORTMESSAGE] => Security error
                    [L_LONGMESSAGE] => Security header is not valid
                    [L_SEVERITYCODE] => Error
                )

        )