New Post: Read column values with Excel Data Reader not working (MVC)

My Excelsheet looks like this:

http://cdn.imghack.se/images/cdc24215d3d5079628a58878520c3028.png


Here is the part of my method that matters:

[HttpPost]
    public ActionResult ShowExcelFile(GetExcel model)
    {
        DataSet result = null;
            var file = model.Files[0];
            if (file != null && file.ContentLength > 0)
            {
                // .xlsx
                IExcelDataReader reader = ExcelReaderFactory.CreateOpenXmlReader(file.InputStream);

                // .xls
                //IExcelDataReader reader = ExcelReaderFactory.CreateBinaryReader(file.InputStream);

                reader.IsFirstRowAsColumnNames = true; // if your first row contains column names
                result = reader.AsDataSet();
                reader.Close();
            }

            for (int i = 1; i < result.Tables[0].Rows.Count; i++)
            {
                DataRow data = result.Tables[0].Rows[i];
                System.Diagnostics.Debug.Write(data.Table.Rows[i]["Amortization"]);
            }
        return View("ShowExcelFile");
        }

System.Diagnostics.Debug.Write gives me no output, like "Amortization" doesn't exist.

My model:

public class GetExcel
    {
        public List<HttpPostedFileBase> Files { get; set; }

        public GetExcel()
        {
            Files = new List<HttpPostedFileBase>();
        }
    }

My HTML:

@using (Html.BeginForm("ShowExcelFile", "ShowExcel", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            @Html.TextBoxFor(m => m.Files, new { type = "file", name = "Files" })<br />
            <input type="submit" value="Upload file" />
        }

But when I use this Excelsheet:

http://cdn.imghack.se/images/1fd5dab2a891c3adda8cd33114ef07c1.png

It works fine and I get all values from column "Amortization" in output. Both files are .xlsx

Can anyone help me with this?