They are included within the theme. Do you have custom breadcrumbs installed in ~/.themes ? If you have installed a breadcrumb hack then you will have to remove it. Press ALT + F2, type: "gedit .gtkrc-2.0" (without quotes) and hit enter. Look for the line: 'include ".themes/nautilus/nautilus.rc"' and delete it. Then reselect this theme in appearance preferences.