When installing WWT, if you install into the default directory, other users that are not administrators will not be able to run WWT unless they install their own copy.
Problem: WWT install into ..\Appdata which is a restrictive folder. When another person logs into the system and tries to run WorldWide Telescope, the program will try to access the folder APPDATA\UserName and since that user doesn’t have permission, the setup will fail.
Solution:
Install WWT into a public folder that all users have access to.