OK for all 3 people in this thread having this issue, I just took five minutes and setup my ps3 controller to work over bluetooth.
Please refer to this guide https://github.com/RetroPie/RetroPie-Setup/wiki/PS3-Controller not some random youtube video when doing this. Also make sure you have at least a keyboard configured to work in ES.
Once you have completed these steps and connected your PS3 controller via USB at least once as it asks you to do in the settings, then all you need to do is press whatever button you have configured as start for your keyboard in ES, then scroll down to configure controller, last HOLD the PS button until it takes you to the next page where you can map the controls! Done.
Oh also don't forget to "sudo nano /etc/rc.local" and add in the sixad --start & somewhere before the exit 0 line. I recommend also adding #This line starts Sixaxis pairing on startup directly above the sixad line so you know what the hell it does, that's just my preference though and has no bearing on making it work and presist through a reboot.