Elastic beantalk: Failed to buld docker image

I'm trying to deploy a Django application to Elastic Beanstalk (AWS). I've started a new Django project from scratch.

When I try to deploy the application, I get the following errors:

ERROR: Failed to build Docker image aws_beanstalk/staging-app: ime="2015-04-02T16:04:13Z" level="info" msg="The command
[/bin/sh -c if [ -f /var/app/requirements.txt ]; then /var/app/bin/pip install -r /var/app/requirements.txt; fi] returne
d a non-zero code: 2" . Check snapshot logs for details.
ERROR: [Instance: i-b9cd0c44 Module: AWSEBAutoScalingGroup ConfigSet: null] Command failed on instance. Return code: 1 O
utput: [CMD-AppDeploy/AppDeployStage0/AppDeployPreHook/03build.sh] command failed with error code 1: /opt/elasticbeansta
lk/hooks/appdeploy/pre/03build.sh

I've tried to keep my project and configuration as basic as possible (still haven't been able to deploy a single django app through AWS, trying to understand what I'm doing wrong..).

In my root folder I have the .ebextensions folder, with the following config file:

container_commands:
  01_syncdb:    
    command: "python testsite/manage.py syncdb --noinput"
    leader_only: true

option_settings:
  - option_name: DJANGO_SETTINGS_MODULE
    value: testsite.settings

I've had to set the WSGIPath variable directly through the elastic beanstalk web GUI - for some reason setting it through the config file just didn't work.

Any ideas?