I woudl suggest that you simplify the install* making it a one-click event of possible;
Remove all the Next button stops. Just stop if things go wrong.
Then also have a message about what went wrong and a button to revert the installation and start over (or similar)
Delete the Install.php file and whatever other cleanup is needed.
I think the options for an un-attended optins are there somewhere. Newbies will not find and use them. I would suggest revertig; single-click install as default* step-trough / parameters as an option.
I would also strongly recommend turning off VB*turning on email verification* turning on moderation of new members as default* with info on the last install screen (checkboxes) to enable things.
I made the misstake of announcing when I would upgrade my old forum to vBulletin* resulting spammers ligning up to get in while the installation was running.
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