Drivers door wont lock

[JezzaMac]

I installed some new component speakers yesterday in the front two doors but now the drivers side door wont lock. The passenger door is fine, what is likely to be the problem and where should I start looking to fix it?

 

[JezzaMac]

What is that black piece at the bottom of the picture? Is it possible that that is not working and therefore stopping the door from locking?

Im really clutching at straws here, any ideas people? Thanks

 

[JezzaMac]

One of you clever people must know of a fix!