You have vBulletin 4.2.0, just like another forums I frequent sometimes.

When you create a new post, there is an Edit button that appear for 30 minutes after you post something. During that time you can go back and fix stupid typos, or add something you didn't think about the first time, etc etc. Think this would be beneficial to us and maybe save some headaches for the moderators cleaning up certain things, that wasn't noticed until after the post.

I just found it extremely odd that you don't have this option enabled.