Error with SSL certificates and SSL Filter

Hi everybody

I am making a proxy and it must support the https protocol. I am trying 
to enable SSL feature in the server side with this command:

POE::Component::Server::TCP->new(
     Alias        => "web_server",
     Port         => LISTEN_PORT,
     #ClientFilter => 'POE::Filter::HTTPD', ##WITHOUT HTTPD FILTER THERE 
ISN'T HTTP HEADERS!!!
     ClientFilter => POE::Filter::Stackable->new(
         Filters => [
             POE::Filter::SSL->new(crt => 'sslkeys/server.crt', key => 
'sslkeys/server.key'),
             POE::Filter::HTTPD->new(),
         ]
     ),

     ClientInput  => \&handle_http_request,
     InlineStates => {got_response => \&handle_http_response,},
);

But when a https request hit the server I get the following error:

POE::Filter::SSL: UNEXPECTED ERROR: ERR1:-1 ERR2:1 HINT: Check if you 
have configured a CRT and KEY file, and that both are readable at 
/usr/share/perl5/POE/Wheel/ReadWrite.pm line 280


I don't know what this error means because the files has the permission 
flags set to 777. Are required some special certs?

Thanks in advance.