I tested the provided code locally and did not have any issues with the upload. The problem is elsewhere, whether with other unprovided code, or with local modules/web service/file system.

Here's a standalone version of the provided code that dumps the file to the browser, along with the temp file name. 

#!/usr/bin/perl
use strict;
use warnings;
use CGI;

my $output   = '';
my $query    = CGI->new();
my $filename = $query->param("uploadfile_0");
my $upload   = $query->upload("uploadfile_0");
$output     .= "Temp file: " . $query->tmpFileName($filename) . "\n";

if (!$upload) {
    $output .= "<p>CGI.pm failed to upload the file.</p>";
}
else {
    $output .= "----- Contents: ------\n";
    while (<$upload>) {
        $output .= $_;
    }
}
print "Content-type: text/plain\n\n";
print $output;

[download]
Could you provide some details about your environment?
e.g.: 
OpenBSD 3.5
Apache 1.3.34
perl 5.8.2
CGI 3.20

In reply to Re: Uploading Files with CGI.pm results in 0 byte files by imp
in thread Uploading Files with CGI.pm results in 0 byte files by Anonymous Monk

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