Hello,
As I understand, you have fatal error on trying to install/activate WP-Property 2.x.x which causes 500 Error. To see the error you should enable debug mode. See doc here.
define('WP_DEBUG', true);
And, be sure, that the errors are being displayed.
define('WP_DEBUG_DISPLAY', false);
Please, let us know, which error occurs on WP-Property 2.x.x activation.
Regards.