K so, the MyBB support forum did fuck all with helping me (whod'a thunk it), so I'm coming here. Basically, the "New Reply" button tries to post a reply for thread 347, regardless of the thread. This thread doesn't even exist, so I have no idea what's causing this. I've checked the New Reply templates to see if that's causing it, but doesn't seem like it. I have a feeling it's related to the Google SEO plugin, but other forums don't have this issue.