Tracking Number of Element (Nods or Sub-Nods) in an XML file

Hello my Code masters,

I beleive you are all doing fine and in good health. I am writing a program that will loop through an XML file and display the total count of the following element's in the file :

Encounter
ART_StartDate
Lab_Reports
Viral_Loads
Regimen

and write out the results in excel, below is the code that i have tried:

//string directoryPath = "D:/TempDir/";
string directoryPath = Server.MapPath(string.Format("~/{0}/", "XML"));
string[] filePaths = Directory.GetFiles(directoryPath, "*.xml"); //, SearchOption.AllDirectories
string fileContent = "";
/*=========================================
* this section is to initialise the Excel header and
* the workbook in turn the worksheet
* */
try
{
ExcelPackage ps = new ExcelPackage();
ps.Workbook.Worksheets.Add("EMR-NDR");
ExcelWorksheet ws = ps.Workbook.Worksheets[1];
object missValue = System.Reflection.Missing.Value;
Session["filename"] ="";
ps.Workbook.Properties.Author = "Abraham Oaltubosun";
ps.Workbook.Properties.Title = "EMR-NDR Data Extraction Analytics";
ExcelRange ChartRange = ws.Cells["A1:D1"];
ws.Cells[1, 1].Value = "Fil Names";
ws.Cells[1, 2].Value = "HIV Encounter";
ws.Cells[1, 3].Value = "CD4";
ws.Cells[1, 4].Value = "Viral Load";
ws.Cells[1, 5].Value = "ART Regimen";
int t = 2;
foreach (string file in filePaths)
{
// Log Message read started
Session["filename"] = file;
fileContent = File.ReadAllText(file).Trim();
if (fileContent.Length > 0)
{
XDocument xd = XDocument.Parse(fileContent);
XmlDocument xxd = new XmlDocument();
xxd.Load(file);
//int HIVEnCounter = xd.Descendants("HIVEncounter").Count();
int HIVEnCounter = 0;
////int RegimenCounter = 0;
int RegimenCounter1 = 0;
int LaboratoryCounter=0;
int ViralLoadCounter = 0;
string result = "";
HIVEnCounter = xxd.SelectNodes("/Container/IndividualReport/Condition/Encounters/HIVEncounter").Count;
string result2 = xd.Element("Container").Element("IndividualReport").Element("Condition").ToString();
if (!result2.Contains("Regimen") && !result2.Contains("Encounters"))
{
result =(string)xd.Element("Container").Element("IndividualReport").Element("Condition").Element("Regimen").Element("PrescribedRegimenTypeCode").Value;
}
if (!string.IsNullOrEmpty(result))
{
if (result == "ART")
{
#region
//RegimenCounter = xd.Element("Container").Element("IndividualReport").Element("Condition").Element("Regimen").Element("PrescribedRegimenTypeCode").Attributes("ART").Count();
//RegimenCounter = xd.Descendants("Regimen").Count();
//RegimenCounter = xxd.SelectNodes("").Count;
#endregion
RegimenCounter1 = xxd.SelectNodes("/Container/IndividualReport/Condition/Regimen/PrescribedRegimenTypeCode[. = \"ART\"]").Count;
}
}
string result3 = xd.Element("Container").Element("IndividualReport").Element("Condition").ToString();
if (result3.Contains("LaboratoryReport") && result3.Contains("LaboratoryResultedTest"))
{
result = xd.Element("Container").Element("IndividualReport").Element("Condition").Element("LaboratoryReport").Element("LaboratoryOrderAndResult").Element("LaboratoryResultedTest").Element("CodeDescTxt").Value;
}
if (!string.IsNullOrEmpty(result))
{
if (result == "CD4")
{
LaboratoryCounter = xxd.SelectNodes("/Container/IndividualReport/Condition/LaboratoryReport/LaboratoryOrderAndResult/LaboratoryResultedTest/CodeDescTxt[. =\"CD4\"]").Count;
//LaboratoryCounter = xd.Descendants("LaboratoryReport").Count();
}
}
string resultVL = xd.Element("Container").Element("IndividualReport").Element("Condition").ToString();
//resultVL = xxd.SelectNodes
if (resultVL.Contains("LaboratoryReport") && resultVL.Contains("LaboratoryResultedTest"))
{
resultVL = xd.Element("Container").Element("IndividualReport").Element("Condition").Element("LaboratoryReport").Element("LaboratoryOrderAndResult").Element("LaboratoryResultedTest").Element("CodeDescTxt").Value;
}
if (!string.IsNullOrEmpty(resultVL))
{
//if (resultVL == "Viral Load")
//{
ViralLoadCounter = xxd.SelectNodes("/Container/IndividualReport/Condition/LaboratoryReport/LaboratoryOrderAndResult/LaboratoryResultedTest/CodeDescTxt[. =\"Viral Load\"]").Count;
//ViralLoadCounter = xd.Descendants("LaboratoryReport").Count();
//}
}
#region
//int CD4Counts = xd.Descendants("CD4").Count();
//int LaboratoryCounter = xd.Descendants("LaboratoryOrderAndResult").Count();
//var border = ws.Cells.Style.Border;
//border.Bottom.Style = border.Top.Style = border.Left.Style = border.Right.Style = OfficeOpenXml.Style.ExcelBorderStyle.Thin; //ExcelBorderStyle.Thin;
#endregion
ws.Cells[t, 1].Value = file;
ws.Cells[t, 2].Value = HIVEnCounter;
ws.Cells[t, 3].Value = LaboratoryCounter;
ws.Cells[t, 4].Value = ViralLoadCounter;
ws.Cells[t, 5].Value = RegimenCounter1;
t = t + 1;
}
else
{
// Log error File is blank
}
}
//============ Download Excel file =====================
//Generate A File with Random name
Byte[] bin = ps.GetAsByteArray();
string files = directoryPath + "\\EMR-NDR.xlsx";
File.WriteAllBytes(files, bin);
Response.ClearContent();
Response.Buffer = true;
Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}", files));
Response.ContentType = "application/ms-excel";
Response.WriteFile(files);
Response.End();
}
catch (Exception ex) { webMessage.Show("Error in "+Session["filename"].ToString()+" :" + ex.Message); }
}

when i run the application i am getting "Object not reference error" kindly assist me, if possible amend where necessary as this application is very crucial to my project analysis success.

I also attached ziped sample xml files to be use for testing.

I appreciate any for of techincal assistance, Thank you all