PayPal and Email issues

I can not get the PayPal plug in to work for me ( I believe I have it set up correctly, but nothing I do will allow me to make a payment. I would appreciate some feedback as to what I am doing wrong.

Also, if I create a trial user and then later delete/remove it from the website, I can not reuse that email. The program will not seem to “let go” and keeps telling me that the email is already in use when it clearly is not. Can I do anything about that?

Thanks for your help.