Eclipse Install new software fails

If you try to add new features from an update site and you get the following strange error:

Cannot complete the install because one or more required items could not be found.
  Software currently installed: Shared profile 1.0.0.1385682248052 (SharedProfile_SDKProfile 1.0.0.1385682248052)
  Missing requirement: Shared profile 1.0.0.1385682248052 (SharedProfile_SDKProfile 1.0.0.1385682248052) requires 'toolingwin32.win32.x86org.eclipse.equinox.p2.reconciler.dropins [3.6.2.M20110210-1200]' but it could not be found

Restart you eclipse as administrator and you problem will be solved.
It fails since you don't have write access to the folder where your eclipse is installed.