Captcha

[Aneth]

Hola!
Estoy iniciando en el uso de perl. Estoy tratando de incluir en mi aplicación el uso de captcha mediante perl. Podrian ayudarme a decifrar este error. !!!
Tome como ejemplo el siguiente código. Donde se debe incluir los directorios correspondientes para imagenes, db, etc. Sin embargo, al ejecutarlo de la siguiente manera http://localhost/perl/captcha.pl

presenta el siguiente mensaje

Error message:
Can't open File: \http\folder\d41d8cd98f00b204e9800998ecf8427e.png ,


Código usado:

use Authen::Captcha;

# create a new object
my $captcha = Authen::Captcha->new();

# set the data_folder. contains flatfile db to maintain state
$captcha->data_folder('/some/folder');

# set directory to hold publicly accessable images
$captcha->output_folder('/http/folder');

# Alternitively, any of the methods to set variables may also be
# used directly in the constructor

my $captcha = Authen::Captcha->new(
data_folder => 'some/folder',
output_folder => '/http/folder',
);

# create a captcha. Image filename is "$md5sum.png"
my $md5sum = $captcha->generate_code($number_of_characters);

# check for a valid submitted captcha
# $code is the submitted letter combination guess from the user
# $md5sum is the submitted md5sum from the user (that we gave them)
my $results = $captcha->check_code($code,$md5sum);
# $results will be one of:
# 1 : Passed
# 0 : Code not checked (file error)
# -1 : Failed: code expired
# -2 : Failed: invalid code (not in database)
# -3 : Failed: invalid code (code does not match crypt)
##############