It should install the skins into the "C:\Program Files\Stardock\Object Desktop\WindowBlinds" folder.
Did you look in this folder after installing to see if they exist?
If they exist, and you are running WB5 beta, have you tried clicking the "refresh" icon below the skin preview pane in the WB configuration panel?
If the above are both false, I would suggest trying the following to see if you can get WindowBlinds to see them:
1 - Unload WindowBlinds using the WB configuration panel.
2 - Use the Display Properties > Themes tab > select Windows XP from the "Theme" drop-down list > click "Apply".
Note - if you are running Icon Packager, use the "Tools > Restore all Icons > click "Yes" to confirm > click "OK" to apply changes, before performing #2.
3 - Reboot machine
4 - Start > Control Panel > Add or Remove Programs > select any listing for "Carbonix" skin pack, and uninstall - then reboot.
5 - Reinstall the Carbonix skin pack, and verify that they install to the "\WindowBlinds" sub-directory.
6 - If they installed correctly, start WB and (if WB5 beta - click the "refresh" ) see if the skins are now visible in the skins listing.
I hope this helps.