Microsoft has introduced a change to the security model in Windows Vista called User Account Control.
Previously, in Windows 2000 or XP, users were either Administrative, Power User or User level. Any programs installed or executed were run with the permissions of the currently logged on user. Many programs, including ITScriptNet, need access to the Registry for registration and licensing, which made it impractical to use User level accounts.
With Vista, Microsoft has changed the way programs are run. By default, all users (even administrators) run programs with a lower level of access, and User Account Control will prompt the user at the console if more rights are needed. The idea is to try and prevent malicious programs from installing themselves without the user being aware of it, while still allowing users to run at the lowest level of permissions possible.
The exception to this is for installation programs, which are run with full Adminstrative rights.
Not all software is compatible with this new model, and will require some changes to work correctly. ITScriptNet requires a change to allow a demo copy of the software to be run without an error message. This update will be released soon.