it turns out this is a bug in MyPad that the developers have not fixed!
anyways, to solve this, you will have to manually delete the message by opening a browser in your iPad and going to this Facebook mobile page:
moderate - no external links!
(note: this is my first post here and since i cannot post a link, just remove all the * in the link above!)
you will find a delete link for every message on that page. delete whatever message you want removed. the next time you access MyPad, those messages are gone.
and yeah, this inconvenience sucks!