Problem with tables with foreign keys

Question

I am trying to make a web application using Netbeans 6.5, MySQL 5.1, JSF, hibernate 3.2 and GlassFish. I want to insert the contents of a form in the database; it works fine when the table doesn't have foreign keys but it doesn't work when they do have them. I tried using Hibernate, and also using an SQL query directly, but it can't get it to work.

public String ok_action() {

    try {
        String m = module.getValue().toString();
        Module mod = new Module(m, null, null, null);
        String nmp = ens.getValue().toString();
        Enseignant en = new Enseignant(null, null, null, null, null, null, null, null, nmp, null, null, null, null);
        Formation f = new Formation();

        f = this.getApplicationBean1().getform();

        Session sess = null;

        sess = HibernateUtil.currentSession();
        Transaction tx = sess.beginTransaction();
        CoursAcc ca = new CoursAcc();
        ca.setEnseignant(en);
        ca.setFormation(f);
        ca.setModule(mod);

        sess.save(ca);
        sess.save(f);
        tx.commit();

        this.getApplicationBean1().setform(null);

    } catch (Exception e) {
        System.out.println(e.getMessage());
    }

    return null;

}