Driver constraint addon error when it is applied : property has not been found I used the driver constraint addon to connect the shapekeys to the bones. The shapekeys come from the manuel bastioni lab and the bones from rigify. I've used two armatures and I have connected them into one only armature called rig. Now I'm trying to use the addon to constraint the bones because I want that when I use the shapekeys also the bones move. The final goal is to convert the shapekeys library into a pose library faster. The problem is that when I go on a shapekey and I do "copy data path",the value copied is not good and it can't be used with the driver contraint addon. It sounds like this : active_shape_key_index ; instead this value should return the name of the shakepey. Anyway,when I use this value the error given is : "bpy_structdriver_add() properly "active_shape_key_index" not animatable". Instead,If i use the name of the shapekeys,the error is "property has not been found". 

You can watch what happens going here : (also the blender file is there) 

https://drive.google.com/open?id=1E4mUhKuKBTZQoIwfnWIGcV6xp8NSgqxb
you made a little mistake in the process of setting up the driver.

You need to copy the datapath of the value. Not the shapekey name. You need to rightclick on the digits and then copy the datapath.

That should do the trick. Then the addon should recognize that you want to key the shapekey value.