Hey folks,
I posted this in a different thread, but this is what I did and it worked for me. I've tried my phone on 3 different docks after I did this and they all work fine. I'll repeat it below, hopefully it will help some of you:
I might add a few steps in case anyone has the same problem and is not as familiar with iTunes as you/me.
1)Connect phone
2)Hightlight your phone on the left side of the iTunes window
3)Click on the music tab towards the top middle of the iTunes window
4)Uncheck "sync music"
5) Click "Apply" down on the bottom right At either this step or the preceding step you might get a
pop up box that says "you have made changes" or something like that, click okay or apply.
6)After this is finished, check to make sure there is no music left on your iPhone by double clicking on your
iPhone in the left hand pane of iTunes and then click on "music" under your iPhone
7)If there is no music on your iPhone, then recheck the "sync music" and then click "apply" down in the
bottom righ.
8)If you have a lot of music it will take hours to sync, but when finished your Dock accesorries should work again.
If I left out any steps, someone please correct me. I'm doing it from memory (which isnt that great)