Invalid Connection String???

[NewbieVB2003]

Set ConnectionInfo = crReport.Database.Tables(1).ConnectionProperties
            
ConnectionInfo.Item("DSN") = dsn_name
ConnectionInfo.Item("User ID") = user_name
ConnectionInfo.Item("Password") = pass_word

When I try to run a report setting the Connection Info as described above,it throws an Error message "Invalid Connection String"
Can anybody please tell me where I went wrong.
Thanks