We managed installation of netbeans 6.8 under windows 8 successfully the following way:
- Don't execute but unzip netbeans-6.8-ml-windows.exe with 7zip (or other unzipper) in an emtpy folder
- execute cmd.exe as administrator
- cd to the folder in which you unzipped the installer
- execute 'java org.netbeans.installer.Installer'
-> installation executes without any errors
