Thanks for taking the time to report this!

Please try 1.22.4 at https://releases.wikimedia.org/mediawiki/1.22/mediawiki-1.22.4.tar.gz and report back.

I downloaded the .tar.gz archive from the link in the ConfirmAccount article,

Plus this needs exact steps to reproduce (preferably a URL). Don't know which of all those "ConfirmAccount article" you mean. :)
I hope you tried with the REL1_22 branch of the ConfirmAccount code repository.

toye.thomas wrote:

The article I'm referencing is located here: https://www.mediawiki.org/wiki/Extension:ConfirmAccount (sorry for the confusion)
I downloaded the latest stable version for MediaWiki 1.22 of the extension from here https://www.mediawiki.org/wiki/Special:ExtensionDistributor/ConfirmAccount

Steps I took:

1. Download MediaWiki 1.22.3
2. Upload to server
3. Do a normal install, using nl (Dutch/Nederlands) as the language and install the following extensions (using the checkboxes in the installation): RenameUser, WikiEditor, Cite, ParserFunctions, SyntaxHighlight
4. Download the ConfirmAccount extension from the source specified (1.22 branch)
5. Create a ConfirmAccount folder in extensions/ on the server
6. Place the files in there
7. Add the following line at the bottom of LocalSettings.php (as mentioned in the article referenced above):

require_once( "$IP/extensions/ConfirmAccount/ConfirmAccount.php" );

8. Navigate to the web-updater (w/mw-config/), I don't have SSH access to the server
9. Select nl (Dutch/Nederlands) again (first page)
10. Click next (to go the second page)

You never get to the second page, instead, it says "Fatal error: Class 'ConfirmAccountUISetup' not found in /home/thomabq55/domains/nmctwiki.eu/public_html/w/extensions/ConfirmAccount/ConfirmAccount.php on line 42"

I'll now try installing MediaWiki 1.22.4 and see if I can reproduce

toye.thomas wrote:

I tried MediaWiki 1.22.4 and I'm gaving the exact same problem.

Can you try https://bugzilla.wikimedia.org/show_bug.cgi?id=55470#c4 ?

toye.thomas wrote:

I added the line
require( DIR . '/frontend/ConfirmAccountUI.setup.php' );

It works now. I'll add this on the wiki page of the extension.