C Sharp Einfügen von Daten in Excel schlägt fehl

        public static bool arrayToExcel(string arrayData, int Rowcount)
        {
            string connectionString = BuidExcelConnectionString(GlobalVarHelper.GlobalPath);
            // Neue OLEDB-Verbindung erzeugen
            OleDbConnection connection = new OleDbConnection(connectionString);

            //Aufbau des INSERT Statement
            string Query = "INSERT INTO [" + GlobalVarHelper.GlobalWorksheet + GlobalVarHelper.GlobalStartPoint + ":" + GlobalVarHelper.GlobalEndPoint + "]";  
            
            //Auslesen und vorbereiten der einzufügenden Werte
            string values = "VALUES(";  
            int valuecounter = 1;
            foreach (string s in arrayData)
            {
                //Stringwerte
                if (valuecounter > 7)
                {
                    values += "'"+s+"'" + ",";  
                    valuecounter++;
                }
                //Numerische Werte
                else
	            {
                    string z = s.Replace(",", ".");  
                    values += ""+z+"" + ",";  
                    valuecounter++;
	            }
            }
            values = values.Remove(values.Length - 1);
            values += ");";  

            //Zusammenbau des kompletten INSERT Strings
            string insertComplete = Query + " " + values;  

            //Ausführen des INSERT Statements
            try
            {
                connection.Open();
                OleDbCommand command = new OleDbCommand(insertComplete, connection);
                command.ExecuteNonQuery();
                connection.Close();
                GlobalVarHelper.GlobalStartPoint = GlobalVarHelper.GlobalStartPoint.Replace("$", "");  
                return true;
            }
            catch (Exception)
            {
                GlobalVarHelper.GlobalStartPoint = GlobalVarHelper.GlobalStartPoint.Replace("$", "");  
                return false;
                throw;
            }
        }