I have a GeeeTech. It has been a while and recall it work straight up, as it is identical pin out as a SparkFun MP3 Shield.
I would suspect that your problem is occurring from some setting between your selected board and the define of MP3_DREQINT that is located in http://mpflaga.github.io/Sparkfun-MP3-Player-Shield-Arduino-Library/_s_f_e_m_p3_shield_config_8h_source.html
