Setup fails on Windows Server 2003 domain controllers


On Windows Server 2003, the group which has the required permissions to execute ASP.NET applications is IIS_WPG and NETWORK SERVICE is part of this group.
See http://msdn.microsoft.com/en-us/library/ms998320.aspx#paght000015_fileaccess.
See also http://learn.iis.net/page.aspx/140/understanding-the-built-in-user-and-group-accounts-in-iis-7/
The issue is on a standalone server this group is MACHINENAME\IIS_WPG whereas on a domain controller this group is DOMAIN\IIS_WPG. We have now introduced a test in the WebInstaller class to check whether the server is a domain controller and refer to the appropriate full name.
This issue does not affect Windows Server 2008 where the group is BUILTIN\IIS_IUSRS in all cases.