My Iphone will not play music through the line out on Dock

[Rustynuts]

I use my iphone at work to play music through my pc monitor, it been working for months untill last week, i thought it was my dock, so i went out and bought a new one and the problem still persists..

One of the guys i work with has a iphone and his works fine on both docks.

My iphone charges and connects to itunes ok it just will not play music through the line in connector, when i dock the phone it continues to play via the iphones built in speakers..

Anyone got any ideas why this is..

Please delete got it working..

For some reason i re-jailbroke the iphone and it worked again. yey

[ToasterBoyOhFour]

i am having the same problem. when docked; it plays through the phones speakers instead of my computer speakers. is there a way around this without having to re-jailbreak it?