Here is my scenario: I am working on migrating a 931 extension to version 10. As per the ESRI link, I have made changes and the revised installer and it works fine. When we went for deployment, the user account that we used before (@931 level) comes back with an error. It throws this error: Error 1001. InstallUtilLib.dll, unknown error. With some accounts with higher privileges, it works fine. it seems like there is a permission issue and I want to know what I need to ask from our System admin to resolve this issue.