Mmmmmm, how about using CGI.pm's upload thingy:

    my $fh = $q->param('file');
    my @name = split(/\./, $fh);

    open (OUT, ">/tmp/.$name[$#name-1].txt");

      {
        my $buffer; my $fbuffer;
        while ( read($fh, $buffer, 1024) ) {
            print OUT $buffer;
        }
      }
[download]

And now for the HTML:

<table border="0" cellpadding="4" cellspacing="0" width="100%" bgcolor
+="#e8e8e8">
  <tr valign="center">
    <form method="post" action="/cgi-bin/tools/app/nmpupload/nmpupload
+.pl?rm=mode2" enctype="multipart/form-data">
      <td width="30%"> <pre> NMP Data File:</pre> </td>
      <td align="right"><input type="file" name="file"> </td>
  </tr>
  <tr>
    <td>
      <input type="hidden" name="rm" value="mode2">
      <input type="submit" value="Upload">
    </form>
    </td>
  </tr>
</table>
[download]

Update: Fixed some missing curly braces...