This is exactly how it worked for me. For some reason the above code failed.
This one runs a check every 3 minutes for any files in there and auto moves it to the destination folder. If you need to be prompted for conflicts then change the /y to /-y
:backup
move /y "D:\Dropbox\Dropbox\Camera Uploads\*.*" "D:\Archive\Camera Uploads\"
timeout 360
goto backup