Before I file an issue over at GitHub, I wanted to post this one here to make sure it’s not a user error.
I would like to add a new contributor. This worked just fine until now.
I go to Poldove -> Mitwirkende (when did that get translated?) -> Hinzufügen.
Then, nothing happens. A blank page:
When I do this, the following entry will be created in my PHP error log:
[20-May-2017 11:23:27 UTC] PHP Fatal error: Call to a member function page() on null in /home/gametalk/public_html/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/lib/settings/expert/tabs.php on line 47
Honestly, I don’t understand what this tries to tell me.
The repair-button didn’t help.
Any ideas? As usual, @ericteubert would be my best bet. 
The code around line 47 is:
public function getCurrentTabPage() {
return $this->getCurrentTab()->page();
}
Website https://GameTalk.FM
PHP Version 5.6.30
WordPress Version 4.7.5
WordPress Theme Joeys Twenty Fifteen Child v1.0
Publisher Version 2.5.2
Web Player Version no web player found
Twig Version 1.32.0
open_basedir ok
curl Version 7.36.0
iconv available
simplexml ok
max_execution_time 50
upload_max_filesize 100M
memory_limit 256M
disable_classes
disable_functions exec, shell_exec, system, dl, passthru, proc_open, proc_close
permalinks ok (/%postname%/)
podlove_permalinks ok
podcast_settings ok
web_player ok
podlove_cache on
assets
0 errors
0 notices
Nice, Everything looks fine!