Ipod + Pioneer deck, subs not working?

[topdogg373]

hey guys im kind of a newbie so please dont work with me here. i currently just hooked up my ipod to my pioneer deck through the AUX and my subs are not outputting any sound, only my 4 in car speakers. this is what im working with.

Pioneer MP-5500
Pioneer P bus AUX input cable
Monster Cable Mp3 Connect
ipod cigarette charger cradle

infinity kappa 60.5 componenets
stock 6x9s
(2) 12' rockford fosgate punch stage one subs
punch 3001 amp

[topdogg373]

can anyone help me? i just talked to the guys at pionner and they told me the loss of sound could be because the power of th ipod needs to be grounded? i dont understand?