Fatal error: Cannot unset $this in /customers/1/a/f/bbqwiki.nl/httpd.www/wp-content/plugins/wp2yt-uploader/classes/class.youtube-for-wordpress.php on line 32

Fatal error: Uncaught Error: Call to undefined function wp_get_current_user() in /customers/1/a/f/bbqwiki.nl/httpd.www/wp-content/plugins/wp-photo-album-plus/wppa-users.php:68
Stack trace:
#0 /customers/1/a/f/bbqwiki.nl/httpd.www/wp-content/plugins/wp-photo-album-plus/wppa-session.php(176): wppa_get_user()
#1 /customers/1/a/f/bbqwiki.nl/httpd.www/wp-includes/class-wp-hook.php(286): wppa_session_end('')
#2 /customers/1/a/f/bbqwiki.nl/httpd.www/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#3 /customers/1/a/f/bbqwiki.nl/httpd.www/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#4 /customers/1/a/f/bbqwiki.nl/httpd.www/wp-includes/load.php(679): do_action('shutdown')
#5 [internal function]: shutdown_action_hook()
#6 {main}
  thrown in /customers/1/a/f/bbqwiki.nl/httpd.www/wp-content/plugins/wp-photo-album-plus/wppa-users.php on line 68