When extracting addons, sometimes the actual addon directories may be enclosed in another directory. You can not just copy addons into sub-directories of the Interface\AddOns directory. The most important file is the .toc file which must be specifically placed for the addon to load correctly. Each directory under Interface\AddOns, must have a .toc file of the same name directly inside. So if you loaded RecordTip it would have Interface\AddOns\RecordTip\RecordTip.toc. All other files, like .tga, .lua and .xml, could be organized into sub-folders in any way the addon author wanted, as long as the .toc file is in the right place and has a reference to the location of the other files, it will work.
I play on Linux, so I don't have any windows screen shots to show the file structure I am talking about.