can someone tell me what I did wrong?

my code below. gives me error message says:
an error has occurred while establishing connection server.  when connecting sql server 2005, failure may caused fact under default settings sql server not allow remote connections. (provider: sql network interfaces, error: 26 - error locating server/instance specified)

my code is:
sqlconnection testconnection = new sqlconnection();
        sqldataadapter testadapter = new sqldataadapter();
        datatable testtable = new datatable();
        int rowposition = 0;

private void mainform_load(object sender, eventargs e)
        {
            this.marketstatus();
            testconnection.connectionstring = @"data source=i:\documents\visual studio 2005\projects\stockproject\stockproject\stocks.sdf;integrated security=sspi";
            testconnection.open();
            testadapter = new sqldataadapter("select * stockinfo", testconnection);
            sqlcommandbuilder testcommandbuilder = new sqlcommandbuilder(testadapter);
            testadapter.fill(testtable);
            this.databasetest();
        }
private void databasetest()
        {
            if (testtable.rows.count == 0)
            {
                txtstocksymboltest.text = "";
                txtlasttrade.text = "";
                return;
            }
            else
            {
                txtstocksymboltest.text = testtable.rows[rowposition]["stocksymbol"].tostring();
                txtlasttrade.text = testtable.rows[rowposition]["lasttrade"].tostring();
            }

        }

        private void mainform_formclosed(object sender, formclosedeventargs e)
        {
            testconnection.close();
            this.close();
        }

the same issue discussed here

 

http://forums.microsoft.com/msdn/showpost.aspx?postid=591597&siteid=1

http://forums.microsoft.com/msdn/showpost.aspx?postid=1645863&siteid=1

 

madhu

SQL Server  >  SQL Server Data Access