Is it a wear and tear kind of thing or can it be fixed under warranty? Whenever i open/close the lid to my PB, there would be creaking sounds (especially when the lid is at around 90 degree angle). It doesn't make it harder to open, the resistance is still the same, but it's just the creaking sound that's bothering me. I just got the PB at the end of this past August... Does anyone else have this same problem?