I hae a pretty old mac running OS X 10.8.5, and when i try to install PD10 (the last version that supports 10.8), everything works until i ask for a trial key. When i put in all my info and everything, and click the button, it gives an error message saying 'Unable to request a trial key' (see attached image) I have already tried the method shown in this article: https://kb.parallels.com/113744.
