I'm pretty sure that the welcome tool was depreciated and no longer works, sorry.

Thanks for the link, it might be useful.

On another note, I want to add a link to the Guidelines of the wiki and to another important page on the welcoming message...

In order to "add an automatic welcome message that would appear for new users", you can take advantage of site notice, but keep it simple. If you need to put several links, just add one link to your community page, where all the first steps, guidelines, community projects, other announcements from admins, and to-do lists can be found. Remember you can edit you community page.