After installing Eclipse on my new Windows Vista installation, I saw that Krugle finally came out with a beta of their Eclipse plug-in so I wanted to install it. At step two (Selecting Help > Software Updates > Find and Install) my Eclipse threw the following error:
Error: "Requested operation cannot be performed because it would invalidate the current configuration. See details for more information." Details: "Platform configuration has been modified outside this program. A restart is recommended".
(This is identical to the error thrown in this Eclipse bug report for Windows 2000, but their solution did not help Vista any.)
Setting the Compatibility mode of Eclipse to “Run as Administrator” solved this problem.