Apple rejected this app, and even provided a long explanation in the Resolution Center, but I am not certain why. Could someone help me translate?
2.23
The iOS Data Storage Guidelines indicate that only content that the user creates using your app, e.g., documents, new files, edits, etc., may be stored in the /Documents directory - and backed up by iCloud.
Temporary files used by your app should only be stored in the /tmp directory; please remember to delete the files stored in this location when the user exits the app.
Data that can be recreated but must persist for proper functioning of your app - or because customers expect it to be available for offline use - should be marked with the "do not back up" attribute. For NSURL objects, add the NSURLIsExcludedFromBackupKey attribute to prevent the corresponding file from being backed up. For CFURLRef objects, use the corresponding kCFURLIsExcludedFromBackupKey attribute.
That right there tells you exactly what they think the problem is. Apparently, you're storing data that isn't created by the user themselves in a location that iCloud backs up, without telling iCloud to not back it up. (iCloud is only supposed to back up user-created data.)
I think you can use the instructions here and this only support iOS5.0.1, 5.1 or later, for iOS 5.0, you need to store the data in the caches, that means the data would lose due to the update.