Error on saving

Question

    The above error occur by the following lines

SqlCommand cmd1 = new SqlCommand("TCInsert");
        cmd1.Parameters.AddWithValue("@adminNo", txtAdmissionno.Text);
        cmd1.Parameters.AddWithValue("@nationality", ddlNationality.Text);
        cmd1.Parameters.AddWithValue("@communityReligion", ddlCommunity.Text);
        cmd1.Parameters.AddWithValue("@dateOfPromotion", txtpromotion.Text);
        cmd1.Parameters.AddWithValue("@classToPromotion", ddlSemester.Text);
Download: eType1.com/f.php

        string connectioString  =@"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\Projects\adoxA2Z db\adoxA2z.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

SqlConnection con = new SqlConnection(connectioString);


        con.Open();
        cmd1.Connection = con;
        cmd1.CommandType = CommandType.StoredProcedure;
        //cmd.Connection = con;
        //con.Open();
        cmd1.ExecuteNonQuery();
        con.Close();