[Plugin: WordPress Wiki] wordpress wiki error

Warning: preg_match_all() expects parameter 2 to be string, array given in /home/xxxx/xxxx/wp-content/plugins/wordpress-wiki/wordpress-wiki.php on line 324

This is the error I get on my website when I try to use the wordpress wiki plugin. Any suggestions what would cause this? I tried changing the theme too, so I don’t think thats the case.

https://www.ads-software.com/extend/plugins/wordpress-wiki/