Is this the security on your machine that you can disable temporarily? If you can you should disable this, then extract the files from the zip, then you can enable it again. Where are you downloading and extracting the files to? You should be downloading the .zip file to a place on your computer then you should extract the contents to a folder in your web root. If you are getting this error when using a particular browser you should try using another browser to see if makes a difference.