I forgot to mention the new method that vBulletin 3.5.X uses to edit thread titles. To edit the title of a thread that you started (this must be done within 24 hours of when the thread was started), instead of clicking on edit in the first post, you double click to the right of the thread title on the forum where the threads are listed. In other words, you don't actually open the post in which you are trying to edit the title; you do so at the forum listing screen. Let me know if you have any questions.