Once the upgrade script runs, you don't need to run it again.
According to my global.php file, this is line 115...
Code:
else
{
$vbulletin->userinfo['lastvisitdate'] = -1;
}
Open your global.php file and scroll down to line 115. Make sure that this is the line you've got.
If you can't add the cookie data, you might have changed your forum URL. Try uploading
tools.php from the
do_not_upload folder. Run it, and try updating the cookie info just in case.