Hello,
I try to upgrade my forum from 4 to 5, I use instruction in this page:
I created a subdomain for that and upload the files: forum.mydomain.com
And then applying instructions I got problem when I do this one: (Rename /vb5/config.php.bkp to config.php.)
When I rename that file to config.php, core/install/upgrade.php doesn't work, when I don't rename it, it works and wants me to enter my customer number, I enter it and in next window, I see this window:

I fill the form and click next but it gives this error:
Error - Could not open frontend config file.
Please refer!
I try to upgrade my forum from 4 to 5, I use instruction in this page:
Setting Up vBulletin 5
Please note that vBulletin 5 has two config.php files. It is very important that both are edited and the values of any overlapping variables like cookie prefix are identical in both files.
5.X specific steps
Running the Upgrade Wizard
Please note that vBulletin 5 has two config.php files. It is very important that both are edited and the values of any overlapping variables like cookie prefix are identical in both files.
- If Upgrading from a previous version, you need to create a backup of your database before proceeding.
- After Purchasing, download vB5 from the your Member's Area.
- Unzip the package.
- Create a new directory to hold vBulletin 5. It should not contain any vBulletin 3 or 4 files.
- Copy the /upload/ your new html folder. For simplicity’s sake, I’m going to assumed it’s been renamed and refer to it as /vb5/.
- Rename /vb5/core/includes/config.php.new to config.php and edit it like you would for vB4. (Change the database credentials & database name.). This is similar to how you installed/upgraded vBulletin 3 and 4.
- Rename htaccess.txt to .htaccess (Note the preceding . IS required)
5.X specific steps
- Rename /vb5/config.php.bkp to config.php.
- Set the cookieprefix to be the same as the one in /vb5/core/includes/config.php.
Running the Upgrade Wizard
- Go to the install directory of core in your browser to install vB5. This is just like installing vB4. Ex: http://www.example.com/vb5/core/install/upgrade.php
- When finished you can view the site through the baseurl (http://www.example.com/vb5).
And then applying instructions I got problem when I do this one: (Rename /vb5/config.php.bkp to config.php.)
When I rename that file to config.php, core/install/upgrade.php doesn't work, when I don't rename it, it works and wants me to enter my customer number, I enter it and in next window, I see this window:
I fill the form and click next but it gives this error:
Error - Could not open frontend config file.
Please refer!
Comment