A little step further.
I delete the old folder with all vbulletin files (/forum/).
I create a new folder with the same name and put inside the 2 files requested by the add-on (an .htaccess and the index.php).
Now when someone click on a vb link the redirect process starts but...
This is exactly what is happening to me?
Any suggestion?
I suppose there is something wrong with
forum.php
index.php
settings within the vbulletin.
Thanks.
:rolleyes::X3:
No, my fault... I find the add-on to install in "add-on" tab.
I thought it will appear automatically.
XF system is really well engineered.
Thanks.
I put a screenshot for people who will have same issue in the future: