Check the path that you installed the addons to first. Here are the mos likely paths to your addons folders:
Windows XP:
C: \Program Files\World of Warcraft\Interface\AddOns\MODFolder\ModName.toc
Windows Vista:
C: \users\public\games\World of Warcraft\World of Warcraft\Interface\AddOns\MODFolder \ ModName.toc
Take a look through this thread also, it may solve your woes:
http://www.wowinterface.com/forums/s...ad.php?t=14762