Iphone 3GS Home Button not working after Touchscreen chnage

Hello,

I have here a iPhone 3GS. In the beginning, the Homebutton was not working, therefore I changed the Touchscreen, but the home button are not working.

Now, I think maybe the iPhone 3GS Dock Connector is not working 100%?

I hope, anyone have some solutions.

thx
Mark83