I found an old post and managed to get this working....

1. First install Informix SE PE (I though servers install last)
2. Configure with SetNet and test a DB using dbaccess
3. Install CSDK in same directory as SE
4. Start sqlexecd using the INFORMIXSERVER you create in SetNet
5. Configure and test ODBC connection.

****** Two remaining issues:

1. Using the "Server Explorer" in Visual Studio .NET to connect to the
ODBC datasource CRASHES "sqlexec" (NOT sqlexecd). Has anyone ever heard
of this?

2. I haven't a clue how to add an additional database user. I added
a user in the Win2k User Manager and gave them admin rights. I did
a grant dba to that user for that databases. The problem is I am
getting "951: Incorrect password or user xxx is not known on the database
server" when I try an connect using the new user. The only way I can
connect is using the user that I log in to the desktop with. Any
ideas?