Wiki plugin - internal linking problem

Hello,
I reopened an old topic (https://premium.wpmudev.org/forums/topic/wiki-plugin-users-cannot-link-to-other-pages-only-admin#post-537171) but didn't get a response, so I try again with a new post.
I have BuddyPress Business Version 4.1.9 with BuddyPress 1.81 and bbPress 2.4.1 installed. Wordpress is version 3.7.1.
Users (some set to subscriber, some to author) are able to edit and add wiki pages but internal linking to other wiki pages isn't available. Wiki privileges are set to "Allow editing by anyone".
I'm adding two screenshots - first I'm logged in as network administrator, then as author with a different account
https://premium.wpmudev.org/forums/?bb_attachments=537171&bbat=34122&inline
https://premium.wpmudev.org/forums/?bb_attachments=537171&bbat=34123&inline