the payPal Payment button are not available for Dreamweaver 8.
the system requiremens for the PayPal Payment Buttons are:
* Windows Vista, Windows XP, or Windows Server 2003
* Dreamweaver CS5, Dreamweaver CS4, Dreamweaver CS3
* Works with static and dynamic pages
Macintosh
* Mac Power PC 10.4.x, 10.5.x
* Mac Intel 10.4.x,10.5.x
* Dreamweaver CS5, Dreamweaver CS4, Dreamweaver CS3
* Works with static and dynamic pages