Moon Dust, if everyone had the ability to do that, someone could come in and delete all their work! Sometimes in a reply, there would be poetic responses to someone - that would all be lost..the camraderie here is what makes PiP so wonderful. If someone could delete a post at any time, our replies would be meaningless...
I understand your frustration when you double post (that button sticks sometimes!). But if you do, just put a note in the post you want deleted, and/or contact a Moderator and we'll be glad to help you.