According to our tipster Topsu, the cause for the delay may be due to a a song in the game's soundtrack, which quotes the Quran. Use of religious text in the game may be considered insensitive to some. We're currently investigating this story, and we'll update when we find out more.
Update: A post on the PlayStation forums discusses the questioned song in detail. SCEE responds: "During the review process prior to the release of LittleBigPlanet, it has been brought to our attention that one of the background music tracks licensed from a record label for use in the game contains two expressions that can be found in the Qur'an. We have taken immediate action to rectify this and we sincerely apologise for any offence that this may have caused."
Update 2: The game will ship the week of October 27th.