I just got my Cookie yesterday.  When I first turned the phone on it asked me for the PUK number.  I called my provider (T-Mobile) and got the number.  After entering the code, it asks for a new 4-digit code which I enter and then re-enter confirm.  The phone says "New password saved" (or something similar, I don't have it with me now).  The next time I power up the phone it asks me for the PUK code again instead of my new 4-digit code.  Apparently it's not saving the new code.  Any help would be greatly appreciated.  Thanks, Bob