I'm attempting to deploy the Dancer2::Tutorial app with Plack::Handler::Apache2 and having problems implementing Sessions using the following setup:
config.yml

appname: "TestSession"
layout: "main"
charset: "UTF-8"

#  session setup
session: YAML
engines:
  session:
    YAML:
      session_dir: /tmp/dancer-sessions

#  template engine
template: "template_toolkit"
engines:
  template:
    template_toolkit:
      start_tag: '[%'
      end_tag:   '%]'
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app.pl

#!/usr/bin/env perl

use FindBin;
use lib "$FindBin::Bin/../lib";

use TestSession;
TestSession->dance;
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TestSession.pm code

package TestSession;
use Dancer2;
our $VERSION = '0.11';
use DBI;
use File::Spec;
use File::Slurp;
use Template;

set 'logger'        => 'file';
set 'log'            => 'debug';
set 'show_errors'    => 1;
set 'startup_info'    => 1;
set 'warnings'        => 1;
set 'username'        => 'admin';
set 'password'        => 'password';
set 'layout'        => 'main';

my $timestamp = localtime;
my $login_status;
my $dbh = DBI->connect('DBI:mysql:testsession','test','dr_dfRFgt@');\
my $flash;

sub set_flash {
     my $message = shift;
     $flash = $message;
 }

 sub get_flash {
     my $msg = $flash;
     $flash = "";
     return $msg;
 }

 hook before_template => sub {
     my $tokens = shift;
     $tokens->{'session_logged_in'} = session('logged_in');
     $tokens->{'css_url'} = request->base . 'css/style.css';
     $tokens->{'login_url'} = uri_for('/login');
     $tokens->{'logout_url'} = uri_for('/logout');
 };

 get '/' => sub {
     my $sql = 'select id, etitle, etext from entries order by id desc
+';
     my $sth = $dbh->prepare($sql) or die $dbh->errstr;
     $sth->execute or die $sth->errstr;
     template 'show_entries.tt', {
         'session_logged_in'    => session('logged_in'),
         'msg'                    => get_flash(),
         'add_entry_url'        => uri_for('/add'),
         'entries'                => $sth->fetchall_hashref('id'),
     };
 };

 post '/add' => sub {
     if (not $login_status) {
         debug "add route attempted with login_status $login_status";
         send_error("Not logged in", 401);
     }
     debug "login_status $login_status: adding entry on status $login_
+status";
     my $sql = 'insert into entries (etitle, etext) values (?, ?)';
     my $sth = $dbh->prepare($sql) or die $dbh->errstr;
     $sth->execute(params->{'etitle'}, params->{'etext'}) or die $sth-
+>errstr;
     set_flash('New entry posted!');
     redirect '/';
 };

 any ['get', 'post'] => '/login' => sub {
     my $err;
     if ( request->method() eq "POST" ) {
        debug "executing login attempt\n";
         # process form input
         if ( params->{'username'} ne setting('username') ) {
             $err = "Invalid username";
             debug "Got Invalid username";
         }
         elsif ( params->{'password'} ne setting('password') ) {
             $err = "Invalid password";
             debug "Got Invalid password";
         }
         else {
             debug "Login Successful";
             session logged_in => true;
             $login_status = 1;
             debug "login_status:".session('logged_in');
             set_flash('You are logged in.');
             redirect '/';
         }
    }

    # display login form
    template 'login.tt', {
        'err' => $err,
    };

 };

 get '/logout' => sub {
    debug "login:\t executng LOGOUT\n";
    context->destroy_session;
    $login_status    = 0;
    debug "login_status on LOGOUT:\t$login_status";
    set_flash('You are logged out.');
    debug "login LOGOUT flash message: ".$flash;
    redirect '/';
 };
start;
true;
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Apache 2 virtualhosts.conf entry.

<VirtualHost 96.0.255.146:80>
    ServerAdmin webmaster@dataship.com
    DocumentRoot /var/www/retireaboard/RetireAboard
    ServerName retireaboard.com
    <Directory "/var/www/retireaboard/RetireAboard">
        AllowOverride None
            Order allow,deny
            Allow from all
    </Directory>

    <Location />
        SetHandler perl-script
        PerlResponseHandler Plack::Handler::Apache2
        PerlSetVar psgi_app /var/www/retireaboard/RetireAboard/bin/app
+.pl
    </Location>
    SetEnv DANCER_ENVIRONMENT "development"
    ErrorLog /var/log/httpd/www.retireaboard.com.log
    CustomLog /var/log/httpd/retireaboard_access.log combined
</VirtualHost>
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httpd error log

[Wed Nov 27 01:15:53 2013] [error] [client 24.86.10.67] Error while lo
+ading /var/www/retireaboard/RetireAboard/bin/app.pl: Unable to create
+ session dir : ./sessions : Permission denied at (eval 135) line 11\n
+Compilation failed in require at /var/www/retireaboard/RetireAboard/b
+in/app.pl line 6.\nBEGIN failed--compilation aborted at /var/www/reti
+reaboard/RetireAboard/bin/app.pl line 6.\n
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Using Plack::Handler::Apache2 to deploy the app with Apache2 causes the compile to fail. The app is unable to create a ./session dir despite having full rwx permissions for the appdir.
Exactly the same failure occurs for JSON sessions.
Is there further Plack setup required in the .pm file?