Powershell scripts read html content by using Html-Agility-Pack

$url = "http://cloudmonitor.ca.com/en/ping.php?varghost=www.silogix.fr&vhost=_&vaction=ping&ping...;
$Path = "c:\temp\Pingtest.htm"

$ie = New-Object -com InternetExplorer.Application 
$ie.visible = $true
$ie.navigate($url)

while($ie.ReadyState -ne 4) { start-sleep -s 10 }

#$ie.Document.Body.InnerText | Out-File -FilePath $Path
$ie.Document.Body | Out-File -FilePath $Path

Add-Type -Path "C:\temp\HtmlAgilityPack.1.4.6\Net20\HtmlAgilityPack.dll"

$webGraber = New-Object -TypeName HtmlAgilityPack.HtmlWeb
$webDoc = $webGraber.Load("c:\temp\Pingtest.htm")
$Thetable = $webDoc.DocumentNode.ChildNodes.Descendants('table') | where {$_.XPath -eq '/div[3]/div[1]/div[5]/table[1]/table[1]'}

$trDatas = $Thetable.ChildNodes.Elements("tr")

Remove-Item "c:\temp\Pingtest.csv"

foreach ($trData in $trDatas)
{
  $tdDatas = $trData.elements("td")
  $line = ""
  foreach ($tdData in $tdDatas)
  {
    $line = $line + $tdData.InnerText.Trim() + ','
  }
  $line.Remove($line.Length -1) | Out-File -FilePath "c:\temp\Pingtest.csv" -Append
}
$ie.Quit()

 ........
  

You cannot call a method on a null-valued expression.
At C:\temp\test_script.ps1:21 char:41
+ $trDatas = $Thetable.ChildNodes.Elements <<<< ("tr")
    + CategoryInfo          : InvalidOperation: (Elements:String) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
 
Remove-Item : Cannot find path 'C:\temp\Pingtest.csv' because it does not exist.
At C:\temp\test_script.ps1:23 char:12
+ Remove-Item <<<< "c:\temp\Pingtest.csv"
    + CategoryInfo          : ObjectNotFound: (C:\temp\Pingtest.csv:String) [Remove-Item], ItemNotFoundExc 
   eption
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.RemoveItemCommand
 
You cannot call a method on a null-valued expression.
At C:\temp\test_script.ps1:27 char:30
+   $tdDatas = $trData.elements <<<< ("td")
    + CategoryInfo          : InvalidOperation: (elements:String) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
 
You cannot call a method on a null-valued expression.
At C:\temp\test_script.ps1:31 char:43
+     $line = $line + $tdData.InnerText.Trim <<<< () + ','
    + CategoryInfo          : InvalidOperation: (Trim:String) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull
 
Exception calling "Remove" with "1" argument(s): "StartIndex cannot be less than zero.
Parameter name: startIndex"
At C:\temp\test_script.ps1:33 char:15
+   $line.Remove <<<< ($line.Length -1) | Out-File -FilePath "c:\temp\Pingtest.csv" -Append
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException