This worked for me:

SqlConnection conn = new SqlConnection();
conn.ConnectionString = "Data Source=XXX.XXX.XXX.XXX,1433;uid=sa;pwd=;Initial Catalog=DPITEST;";
conn.Open();
this.button1.Text = "Open!";
conn.Close();
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter("select * from client",conn);
da.Fill(ds);
this.dataGrid1.DataSource = ds.Tables[0];

Use the ip address.

>David,
>
>This is too weird. The connection string seems to work perfectly is any other solution except for the Smart Device Application.
>
>The error:
>
>System.Data.SqlClient.SqlException: SqlException
>
>
>very, very informative...
>
>I will try to find a workaround.
>Thanks for all your help.
>
>Regards,
>
>Alvin