Hello,
Since a long time i haven’t played with Cairo-Dock, so i decided to give it a try.
But, it seems like some people just like me, encounter trouble launching Caja with Cairo-Dock.
I solved that problem following those steps :
Drop Caja to the dock to become a launcher
Edit that Caja-Launcher by right clicking on it
I don’t have that menu in english but you should be able to see on the last line something like :" command to launch on click"
Then copy and past this :
caja ""
Apply the change
Caja should now be able to launch properly !
Wish this could help 