I’m afraid that I don’t have any personal experience with this LCD.
Have you followed the Adafruit tutorial on wiring and programming this display ( http://ladyada.net/products/nokia5110/ ) ? They also have a support forum for LCD display issues, which is probably the best place to ask questions like these ( http://forums.adafruit.com/viewforum.php?f=47 ). There are several questions in the forums there that may be related, and it stands to reason that other people who have been through these issues do frequent these forums.
-Windell
