connects2 sound distortion

this week i purchesd a connects2 ipod adaptor and fitted it yesterday {good friday }

to my stream radio after fitting and putting the whole thing back together again sound was distorted { crackling,echoes,}

after removing the radio i connected the block where the cd changer went next i was'nt sure about the earth's so i connected both black cables that came with the the unit

however there was a green cable that was loose so i pushed back into the block wich was already in place so if anyone has any ideas i would be grateful

ps. i have tried a couple of usb sticks

will