## previous code 
$Response->{'Buffer'} = 1;

$Response->{ContentType} = "application/vnd.ms-excel";
$Response->AddHeader('Content-Disposition', "attachment; filename=$filename");
#    'Specify size so that the browser's progress bar works properly
$Response->AddHeader( "Content-Length", -s $long_filename);

open(IN, "<$long_filename") || AppendToLog("Unable to open yada yada ");
binmode(IN);
my @buf = <IN>;
close(IN);

BinaryWrite(@buf);

$Response->Flush;

## more code


sub BinaryWrite(@) {
	my $output;
	foreach $output (@_) {
		if (length($output) > 128000) {
			BinaryWrite(unpack('a128000 a*', $output));
		} 
		else {
			my $variant =Win32::OLE::Variant->new(VT_UI1, $output);
			$Response->BinaryWrite($variant);
		}
	}
}