Download Carbonite from
HERE and save it to your desktop.
Navigate to your WoW addons folder.
-- Using Windows XP? This is your default install directory
(C: \Program Files\World of Warcraft\Interface\AddOns\)
-- Using Windows Vista? This is your default install Directory
(C: \users\public\games\World of Warcraft\World of Warcraft\Interface\AddOns)
-- If you used a custom install directory then you know where it is.
Once you have a window open to your WoW's addon folder then double click the Carbonite-3.100.zip file you just saved on your desktop.
DRAG the folders in the Carbonite window that opened up to your WoW addon folder. Be careful not to DROP the three Carbonite folders onto another folder in the WoW addons folder.
For more help you can refer to this FAQ
HERE
Also seeing how you have an older version installed I would suggest you delete any Carbonite folders from the WoW addon directory before moving the new on there.
Hope this helps.