Nhibernate.Util causing ProxyFactoryFactoryNotConfiguredException when configuration line exists in config
NHibernate.Bytecode.ProxyFactoryFactoryNotConfiguredException:
    The ProxyFactoryFactory was not configured.
    Initialize 'proxyfactory.factory_class' property of the session-factory
    configuration section with one of the available NHibernate.ByteCode providers.
    Example:
    <property name='proxyfactory.factory_class'>
    NHibernate.ByteCode.LinFu.ProxyFactoryFactory, NHibernate.ByteCode.LinFu
    </property>
    Example:
    <property name='proxyfactory.factory_class'>
    NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle
    </property>
    [Continues down stack trace...]

<?xml version="1.0" encoding="utf-8" ?>
   <hibernate-configuration  xmlns="urn:nhibernate-configuration-2.2" >
    <session-factory name="Linx2">
  <property
        name="connection.driver_class">NHibernate.Driver.NpgsqlDriver</property>
      <property name="dialect">Linx2.Common.Framework.PostgreSQL83Dialect,
        Linx2.Common.Framework</property>
  <property name="connection.connection_string">[Hidden so I don't get fired.]</property>
      <property name="adonet.batch_size">10</property>
  <property name="show_sql">false</property>
  <property name="use_outer_join">true</property>
  <property name="command_timeout">60</property>
  <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
      <property name="proxyfactory.factory_class">
         NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle
       </property>
        <property name="connection.release_mode">after_transaction</property>
        <mapping assembly="NHibernate.Collection.Observable" />
    </session-factory>
   </hibernate-configuration>

if (NHibernateUtil.IsInitialized(ChildAssociations))
                {
                    ChildAssociations.ForEach(x => isValid = isValid && x.Element.IsValid(validatedObjects));
                }

var cfg = new NHibernate.Cfg.Configuration().Configure();
var sessionFactory = cfg.BuildSessionFactory();