This works with perl5 (revision 5 version 16 subversion 1):

#!/opt/perl/bin/perl
use warnings;
use strict;
use diagnostics;
use Archive::Zip qw( :ERROR_CODES :CONSTANTS );

MAIN: {
    my $zd = 'foobar';

    my $zip = Archive::Zip->new();

    my $d = $zip->addDirectory( $zd );

    my $f = $zip->addString( 'this is a test', "$zd/foo.txt" );

    $f->desiredCompressionMethod( COMPRESSION_DEFLATED );

    $f = $zip->addString( 'of the emergency broadcast system', "$zd/ba
+r.txt" );

    $f->desiredCompressionMethod( COMPRESSION_DEFLATED );

    unless ( $zip->writeToFileNamed("$zd.zip") == AZ_OK ) {
        die 'write error';
    }

    exit 0;
}
[download]

$ unzip -l foobar.zip
Archive:  foobar.zip
  Length     Date   Time    Name
 --------    ----   ----    ----
        0  09-28-12 11:18   foobar/
       14  09-28-12 11:18   foobar/foo.txt
       33  09-28-12 11:18   foobar/bar.txt
 --------                   -------
       47                   3 files
$