I am trying to install Sql Server 2005 June CTP on a Windows Server
2003 SP1 primary domain controller with IIS/ASP installed.
I get this error (when Sql Server Database Services is being installed:
"SQL Server Setup was unable add user NT AUTHORITY\NETWORK SERVICE to
local group SQLServer2005MSSQLServerADHelperUser".
And I am not alone!
See http://forums.microsoft.com/msdn/ShowPost.aspx PostID=18788
Any workaround or update to be able to install it on a domain controller, Microsoft
Thanks!

Cannot install June CTP on Windows 2003 DC !!!
Waldo A. Flores
MSTSE
Our environment requires installation of SQL 2005 on a server with Active Directory... so this is really a big issue.
Please, can somebody from MS look into this
Allen_Simmons
Brian Evans
Can somebody from Microsoft please respond
Scott Glass
Currently SQL Server 2005 will not install on a Domain Controller or on Windows Small Business Server. There is no known work around at this time other than installing on a machine that is not configured as a domain controller. This is a known issue and we're working on resolving it.
Dan