I got a Facebook Page Tab App (using Timeline). It works fine in desktop version of Facebook, but when its Wall Post is clicked in Facebook App, it returns "The page you requested was not found" and forwards to an inaccessible link:
https://m.facebook.com/4oh4.php?id=282832318433409&_rdr
How come? I don't expect mobile version will be the same as desktop version, but I don't expect it reports the page cannot be found.
Page tabs apps are not supported (as of April 2012 anyway) on mobile browsers - mobile apps are, but they're not tied to the Page and need to be manually linked-to or bookmarked, the tab functionality simply doesn't exist now.