Problems with nuelectronics' LCD + Joy

Hey there, I'm new to the Arduino platform. I find it really interesting ;)

Some days ago I bought a "Color LCD & Joystick shield for Arduino". I have a problem though.. Sometimes it shows a magenta color screen while running and sometimes when it starts. I think it's "crashing". Could it be a hardware problem or a software problem (library)? :-/

I read somewhere that this library (downloaded for the nuelectronics' site) only works with Arduino 13, if I recall corectly. :'(

Sorry for my English, I'm doing my best! :-[

Well, Internet doesn't have the answer (at least I couldn't find it). You need to power the board with a power supply. That fixed the problem.