Script to copy files over filtered by list metadata

Looking to copy files to a external drive. I want to only copy the files that fit a date inside the metadata that I provide. I am using closed data to do this. Here is my script.  Below is my script.  Not sure why its failing.  Can someone point out probably the simple thing I am missing

######################## Start Variables ########################
######################## Dave's Script######################
$destination = "D:\Extract"
$webUrl = "https://test"
$listUrl = "https://test/sites/Area7/conversion%20test"
##############################################################
$startdate = [datetime]'9/20/2017 12:00:00'
$enddate   = [datetime]'9/22/2017 12:00:01'
$web = Get-SPWeb -Identity $webUrl
$list = $web.GetList($listUrl)
[datetime]$datevar = $item["DateClosed"]

function ProcessFolder
{
    param($folderUrl)
    $folder = $web.GetFolder($folderUrl)
    foreach ($file in $folder.Files)
    {
 if($datevar -gt  $startdate -and  $datevar -lt $enddate)
 {
         #Ensure destination directory
         $destinationfolder = $destination + "/" + $folder.Url
         if (!(Test-Path -path $destinationfolder))
         {
             $dest = New-Item $destinationfolder -type directory
         }
         #Download file
         $binary = $file.OpenBinary()
         $stream = New-Object System.IO.FileStream($destinationfolder + "/" + $file.Name), Create
         $writer = New-Object System.IO.BinaryWriter($stream)
         $writer.write($binary)
         $writer.Close()
        }
    }
}

#Download root files
ProcessFolder($list.RootFolder.Url)
#Download files in folders
foreach ($folder in $list.Folders) {
    ProcessFolder($folder.Url)
}