Since we do not claim ownership of the submissions, no, the only person who can give you permission to use their work is the actual author of any given piece. Many authors have some sort of contact information (their email, twitter, tumblr, etc) as their credit link; please do use that to contact them – you do not need to involve us at all, as we claim no rights to their work. If there is no credited author and the piece you’re interested in was posted AFTER JUNE 2012, we may be able to help you by forwarding your request/contact information to the author, but we cannot promise they will reply. Anything before June 2012 is out of our hands, your best bet is to simply use Google to see if you can track down the author.
DO NOT SIMPLY TAKE THE WORKS HERE FOR YOUR OWN PROFIT. Many of the people contributing to this website are attempting to get themselves out there and noticed so that they can get a book deal in the future; when you steal their work, alter it, and spread it all over the internet for your own self-promotion, you are being both incredibly dishonest as well as directly hurting the author. If you are interested in using a pasta for ANY reason, please make an honest effort to get permission from the author first; if you cannot get ahold of the author, err on the side of caution and refrain from using their work.
Remember that when the author submitted, they gave permission specifically to creepypasta.com to use their work; they did not give permission to the internet at large. This means that authors are well within their rights take legal action against you if you steal their work and they object to how you’re using it.