my $filename = "MyDoc.csv";
my $file = "C:\\" . $filename;
$request=POST $upload_url,[
              Content_Type => 'multipart/form-data',
              $file, $file,                       # what is that supposed to be?
              Content => [
                  'upload' => [$file,$filename]], # please explain this line!
                  submit => 'Upload',
                  Upload => 1,
                  theFile=>$file                  # ... and this line too
             ];