There is a "paypal_pro" plugin, but I believe alex is still clarifying whether that is PayFlow or Payments Pro. You have to enable the "cc" plugin, then "paypal_pro" will show up in your payment plugins and will ask for the API information.
I'm going down this road right now myself. So I started with just getting our paypal account setup (Business account). Then I got PayPal Payments Pro setup... (this is still under my main paypal login). With PayPal Payments Pro you can go to: Profile -> More Options -> My Selling Tools -> API Access From there you can get the API login setup for Amember... (**whew**) THEN... if you want recurring payment capability, you have to go to the little link at the top for "Go to PayPal Manager" (you'll be asked for this login info upon initial setup...) then from within your paypal manager login (https://manager.paypal.com) you can order PayFlow Link or PayFlow Pro and recurring payments. So I just paid $198 to get that all setup with of course additional monthly charges (Yay!).. SO... I initially ordered PayFlow Link which isnt as bad a monthly charge... but when I called in they said for API calls from a website billing system I'd need to upgrade to PayFlow Pro!! Which was another $70 setup fee AND $30 per month instead of the $19 per month for PayFlow Link... So after all this - it's still unclear to me if Amember is even going to work with PayFlow (Link?? or Pro??)
There is no payflow_pro support yet And you don't need it. Use paypal_pro plugin in aMember instead. Also I've seen your post about error, will reply in that post as well.