In \wp-content\themes\saasland\inc\classes\saasland_register_theme.php, open saasland_register_theme.php and find:
if( isset($_POST['saasland_purchase_code']) ) {
Change it to:
//if( !isset($_POST['saasland_purchase_code']) ) {
Then find:
if ( is_object($o) ) {
Change it to:
//if ( !is_object($o) ) {
Save the file then insert any license key in the WordPress screen. To install demos, remember to install all the required plugins first.