Using with Gear4 Street Party 111

I am an mp3 player idiot so bear with me.  I bought a Fuze a month ago and was advised that it would work great with Gear4 speakers.  I have purchased Street Party 111 and it works OK with the cable but not when I put it into the dock.  I have made sure the firmware is up to date (Version 2)  Am I doing something wrong - am I a totally numpty have I bought the wrong MP3

Thanks