I am trying to post a reply in a thread in the plugins forum and I cannot. I get a 403 forbidden error everytime that I do. I couldnt find a contact email or anything so I apologize if this is the wrong place to put this. I have tried logging out and back in as well as a different computer with a fresh cache. Please help

If you are able to post here, you should be able to post in User Customizations as well (I assume that is the subforum you are talking about).  Are you still having this issue?  I've had issues myself from time to time since my browsers remember my login info.  Try clearing your browser's cache and saved passwords, then logging in again.

I believe I read about a user trying to post and getting an error like you. Are you trying to post with a link to anything? If so try doing so without the link and see if it works.