Installing : Installing System Architect : Post‑installation tasks : Configuring user access rights to servers, catalogs, and encyclopedias : Permitting connections to SQL Server Express from a client computer
  
Permitting connections to SQL Server Express from a client computer
In Windows 2003, for a System Architect client to connect to Microsoft SQL Server Express, you must set the TCP/IP protocol on the server, or a connection error might occur.
1 On the server, click Start > All Programs > SQL Server Configuration Manager.
2 Select the SQL Server 2005 Network Configuration node, and then click Protocols for SQLEXPRESS.
3 Right-click TCP/IP, and then click Enable.
4 Close the SQL Server Configuration Manager.