[Opserty]

Instead of asking questions, read the instructions on the page provided:

so now my usergroup and my account cant be deleted?

$config['SpecialUsers']['undeletableusers']

If your vBulletin installation is going to have multiple users with administrative privileges, you may wish to protect certain users from accidental (or even malicious) deletion or editing. Any user IDs entered into this list will not be editable or deletable from the Administrators' Control Panel by anybody.

after what part do i add ?>

because i cant see that inside my config.php file..

Note: When editing config.php, make sure there is no whitespace or extra lines either before the <?php or after the ?>. If there are any extra lines or space, you will see an 'Unable to add headers' error when accessing your forums.

Note:
Later versions of vBulletin may not have the ?> at the end. This is to help prevent this kind of error from happening.

Once you have finished editing your config.php file you should save it again and prepare to upload the file to your web server.

Just a bit of reading will get you the answers. Just put in a bit of effort before you ask, it will only make you a better admin.