Reg R/3 4.6c installation on Windows 2003 Server

Dear Experts,

I want to install SAP R/3 4.6c on Windows 2003 SErver and with Sql SErver 2000. Does SAP support this installation.Whenever i try to do this installation i get an error as below, after 70% of the installation gets over

Msg 15401, Level 11, State 1, Server ... , Procedure sp_grantlogin Line 41

Windows NT user or group .... not found. check the name again.

This message on the windows states that the error message is due to the inability to add the user account to the sql server database which is been used for installation.

Any help to overcome this problem will be appreciated. This is very important as i want to bring up the system as early as possible for testing.

Regards,

Karthik