To install and run fluxkraft your web server must meet certain minimum requirements.
See the general requirements for Drupal: https://drupal.org/requirements
However, fluxkraft is required to be used with PHP 5.3.2 or higher.
Also set your PHP memory limit to at least 128MB or better 256MB: https://drupal.org/node/207036
It is highly recommended to set up a server cron job: https://drupal.org/node/23714. For testing and certain use-cases Drupal's built-in triggering of cron runs may be sufficient, but note that Drupal will only trigger cron runs if someone is visiting your site.