Issue: Wiki does not work after beta 5 upgrade.

Somehow you had not gotten the new code event listeners for Beta 5, so XenForo couldn't handle a dynamic wiki route. Running the upgrade script again fixed this problem, but revealed another issue, which showed the same error message in the OP.

There was no XenForo handling for non-friendly wiki URLs. Only friendly wiki URLs would pass to a page, otherwise the route would fail. Fixed in your test install and in build 005.

The data for the wiki index page gets cached. To clear the bad route for the wiki index, go to the VaultWiki Admin Panel, Settings > Site Config, and change the File Name to just "wiki". This should clear the cache entry for the index, as well as make your URLs slightly prettier. Just my opinion, but I think this name looks better for XenForo's URL structure (and I believe it's the default now for new XenForo installs).

The VW admin panel is gone, while there are two links to the upgrade script.

EDit: the second link pointed to VW adminCP.
I changed wiki urls to /wiki/Prefix:Article but it displays as wiki_index instead. Seems like another bug.
EDIT2: now I get the original error again.

If you can give my account admin privileges it will make it easier to debug the admin panel things.

The URL format just changes the directory STRUCTURE.
The name of the directory is still controlled by the Wiki File Name setting, which you still have set to "wiki_index".
It seems there's a problem using underscores in the directory name when friendly structures are selected.

wiki instead of wiki_index would indeed be much better.
If I change it to wiki in the settings then I would also need to change the file name itself?
You have admin prioveledges.

You don't need to change the file name. There is no separate wiki file in XenForo anymore.

Fixed the issue with _ in the directory path for the next release. Also fixed an issue where changing the directory path fails to update certain pages. Fixed the issue with the index path not updating on rebuild on your install.

These changes will be applied to the next build of Beta 5.

Which build is that? I have installed build6 now but i am not sure if that should include the patch. The wiki still does not work.

Try to change the wiki file name setting from "wiki_index" to just "wiki". If your wiki works afterwards, then the patch worked.

Its not working. html response: 'The page is not redirecting properly'

There were no path entries in the database from before the patch was applied. I have rebuilt these for you, so you should have access now.

thanks!