For the newest iOS release (1.31): If you can't delete posts from your wall, try switching to your friends then back to your wall. We're working on getting a fix out soon. If you're still experiencing problems, let us know via Feedback or email. Thanks for your patience everyone! EDIT DEC 13: PIMD 1.32 is now out, which fixes this bug.
If switching doesn't work then you just haw to wait for ATA to fix this issue and be patient patients is the key to everything.
Slender, switching at first didn't work for me either. But when I switched and my friend list loaded completely, and then switched back, then I could delete messages. Try that if you didn't let the friend list load completely. (So if the little rotating white circle was still there)