i am trying to re-install the latest WWT on a Dell Inspiron 6000 notebook computer running XP sp3 for my brother, who is an earth science teacher. he had a previous version working ok, but uninstalled that after some sort of update problem. when we run the installer for the latest, "hotfix" version found at: http://content.worldwidetelescope.org/update/wwtsetup.msi it fails after the license agreement with the message: "the system cannot open the device or file specified" after