Ungültiger Spaltenname SQL-Server

Immer, wenn ich meine form, es gibt mir eine Fehler-code:

"Ungültiger Spaltenname" für alle eventspecialist, Telefon, phon2, etc. und @FACHARZT, @CUST_PHONE, @CUST_PHONE2, etc.

Hier ist mein code vielleicht bin ich nicht das schreiben der SQL-Anweisung oder ein Parameter richtig? Diejenigen, die mit @ infront sind, was in meine Datenbank, und die anderen Kleinbuchstaben sind meine Textfelder. Ich bin relativ neu bei dieser Art der Codierung.

Edit: Änderte meine INSERT INTO-Anweisung zu dem, was vorgeschlagen wurde. Der Fehler weiterhin besteht, aber nur minimiert

"Ungültige Spalte name eventspecialist, Ungültige Spalte name Telefon, Ungültige Spalte name phone2, etc."

private void execution(string eventspecialist, string phone, string phone2, string firstname, string lastname, string besttime, string companyname, string nonprofit, string requesteddate, string requestedtime, string attendance, string eventtype, string other, string leadsource, string notes, string catering, string bar, string damagedeposit, string dancefloor, string griddate, string gridnotes, string comments)
{
    SqlConnection conn = new SqlConnection(GetConnectionString());

    string sql = "INSERT INTO tblcontacts (@SPECIALIST, @CUST_PHONE1, @CUST_PHONE2, @CUST_FNAME, @CUST_LNAME, @BEST_TIME, @COMPANY_NAME, @NONPROFIT, @REQ_DATE, @REQ_TIME, @ATTENDANCE, @EVENT_TYPE, @OTHER_DESC, @LEAD_SOURCE, @NOTES, @CATERING, @BAR, @DAMAGE_DEPOSIT, @DANCE_FLOOR) VALUES (eventspecialist, phone, phone2, firstname, lastname, besttime, companyname, nonprofit, requesteddate, requestedtime, attendance, eventtype, other, leadsource, notes, catering, bar, damagedeposit, dancefloor)";
    string sql2 = "INSERT INTO tblnotes (@NOTEDATE, @NOTEBY, @COMMENTS) VALUES (griddate, gridnotes, comments)";

    try
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql, conn);

        cmd.Parameters.Add("@SPECIALIST", SqlDbType.NVarChar, 50).Value = eventspecialist;
        cmd.Parameters.Add("@CUST_PHONE1", SqlDbType.NVarChar, 50).Value = phone;
        cmd.Parameters.Add("@CUST_PHONE2", SqlDbType.NVarChar, 50).Value = phone2;
        cmd.Parameters.Add("@CUST_FNAME", SqlDbType.NVarChar, 50).Value = firstname;
        cmd.Parameters.Add("@CUST_LNAME", SqlDbType.NVarChar, 50).Value = lastname;
        cmd.Parameters.Add("@BEST_TIME", SqlDbType.NVarChar, 50).Value = besttime;
        cmd.Parameters.Add("@COMPANY_NAME", SqlDbType.NVarChar, 225).Value = companyname;
        cmd.Parameters.Add("@NONPROFIT", SqlDbType.NVarChar, 10).Value = nonprofit;
        cmd.Parameters.Add("@REQ_DATE", SqlDbType.Date, 20).Value = requesteddate;
        cmd.Parameters.Add("@REQ_TIME", SqlDbType.Time, 20).Value = requestedtime;
        cmd.Parameters.Add("@ATTENDANCE", SqlDbType.Int, 50).Value = attendance;
        cmd.Parameters.Add("@EVENT_TYPE", SqlDbType.NVarChar, 50).Value = eventtype;
        cmd.Parameters.Add("@OTHER_DESC", SqlDbType.NVarChar, 225).Value = other;
        cmd.Parameters.Add("@LEAD_SOURCE", SqlDbType.NVarChar, 50).Value = leadsource;
        cmd.Parameters.Add("@NOTES", SqlDbType.NVarChar, 225).Value = notes;
        cmd.Parameters.Add("@CATERING", SqlDbType.NVarChar, 1).Value = catering;
        cmd.Parameters.Add("@BAR", SqlDbType.NVarChar, 1).Value = bar;
        cmd.Parameters.Add("@DAMAGE_DEPOSIT", SqlDbType.NVarChar, 19).Value = damagedeposit;
        cmd.Parameters.Add("@DANCE_FLOOR", SqlDbType.Money).Value = Decimal.Parse(dancefloor);


        cmd.CommandType = CommandType.Text;
        cmd.ExecuteNonQuery();
    }
    catch (System.Data.SqlClient.SqlException ex_msg)
    {
        string msg = "Error occured while inserting";
        msg += ex_msg.Message;
        throw new Exception(msg);
    }
    finally
    {

        conn.Close();
    }
    try
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand(sql2, conn);

        cmd.Parameters.Add("@NOTEDATE", SqlDbType.Date, 50).Value = griddate;
        cmd.Parameters.Add("@NOTEBY", SqlDbType.NVarChar, 50).Value = gridnotes;
        cmd.Parameters.Add("@COMMENTS", SqlDbType.NVarChar, 50).Value = comments;

        cmd.CommandType = CommandType.Text;
        cmd.ExecuteNonQuery();
    }
    catch (System.Data.SqlClient.SqlException ex_msg)
    {
        string msg = "Error occured while inserting";
        msg += ex_msg.Message;
        throw new Exception(msg);
    }
    finally
    {

        conn.Close();
    }

}
protected void Page_Load(object sender, EventArgs e)
{
    griddate.Text = DateTime.Now.ToString("yyyy/MM/dd");
}
protected void submit_Click(object sender, EventArgs e)
{
    if (requesteddate.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else if (requestedtime.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else if (attendance.Text == "")
    {
        Finish.Text = "Please complete the form!";
    }
    else
    {
        execution(eventspecialist.Text, phone.Text, phone2.Text, firstname.Text, lastname.Text, besttime.SelectedItem.Text, companyname.Text, nonprofit.Text, requesteddate.Text, requestedtime.Text, attendance.Text, eventtype.SelectedItem.Text, other.Text, leadsource.SelectedItem.Text, notes.Text, catering.Text, bar.Text, damagedeposit.Text, dancefloor.SelectedItem.Text, griddate.Text, gridnotes.SelectedItem.Text, comments.Text);
        Finish.Visible = false;
        conform.Visible = true;
    }
}