I'm in the same boat as others are. I'm almost 100% certain that I never changed my passcode, yet it won't accept it--and this happened after the latest iOS 5 upgrade. I had turned on restrictions to prevent any apps from doing an unauthorized in-app purchase... you know, the kind where you indavertently tap on something in an app and suddenly are getting charged.
Unfortunately, with iOS 5, there is no SBParentalControlsPIN in the springboard. Where is the code kept now?
Again, as others have indicated, I'm using my own iPhone, but the darn passcode no longer works!
The idea of having to restore this as a new iPhone and then re-download everything--and lose key items-- is ridiculous! (One can't do a Backup because that brings back the hidden passcode). Doing a full restore as new will lead to loss of folders, ebooks, pref settings (and we've tailored dozens of apps; plus many are complicated-- latitutde and longitude by decimal or degrees), and, worst of all, ebook and dictionary bookmarks.
I agree with the suggestion that there should be other, easier ways of iPhone owners recoving their passcodes-- e.g., via sending an e-mail from your official e-mail address and getting it in return. I'm sure there's a way of doing this to prevent the kids hacking parental controls-- but sparing all legitimate owners, parents and non-parents, these incredible hassles.
In fact, why not have a system where owner can *optionally* choose to set restrictions that aren't passcode related?