|In FAQ 287, we explain when and why to apply the hotfixes. The readme.txt for each hotfix zip (downloadable from the web site) explains how to apply the fixes, and one for the .NET edition explains that for some types of installations you must drag and drop the updated DLLs to the "global assembly cache" (or GAC) located at windows\aseembly directory (and that you can't copy and paste them).
But the hotfixes are in a zip file, and while Windows may permit you to open that zip file to view it as if it is a regular directory, you'll find that when you try to drag the files out of the "directory", it won't work.
The problem is simply that you must first extract the zip file (or copy/paste the files to a regular directory first), and then drag/drop the files from there to the GAC (windows\assembly directory). Don't forget to restart IIS afterward.