>>>When I try to install Infragistic NetAdvantage for .Net I receive an error message.
>>>
>>>I followed everything mentioned for Vista (UAC and IIS) but still I get the following error
>>>
>>>Error 1609. An error occured while applying security settings. Administrator is not a valid user or group. This could be a problem with the package, or a problem connecting on a domain controller on the newtwork. Check your network connection and click Retry or Cancel to end the install.
>>
>>Hi Denis.
>>
>>UAC is off, right?
>>
>>Have you tried getting ownership of your folders?
>
>Yes UAC is off. I'm not sure I understand well what you mean by ownership of my folders. I always log as Admin.

It's just a thought... I installed it over here (version 7) and it went alright.

About the ownership, have a look at this KB
http://support.microsoft.com/kb/308421/en-us