How to activate Zephyr theme

Go to wp-content\themes\Zephyr\common\admin\functions\about.php, after line 63 add this:

 update_option( 'us_license_activated', 1 );
 update_option( 'us_license_secret', 'secret_goes_here' );

You are ready to go. Zephyr is activated and importing demos works fine.