Hibernate association references unmapped class exception

I have the following class:

public class Car implements Comparable<Car>{

private long idCar;

private String model;

private String immat; //Car License Plate

private Company company;

private Manufacturer manufacturer;    

private Calendar registrationDate;

private Calendar lastControlDate;

//Has empty constructor + Getters and setters here onwards...

and it's hibernate configuration file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"      "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class name="Car" table="cars" lazy="true"> 
    <id name="idCar" type="long" column="idCar">
      <generator class="native" />
    </id>

    <property name="model" type="string" column="model" />
    <property name="immat" type="string" column="immat" />
    <property name="registrationDate" type="date" column="registrationDate" />
    <property name="lastControlDate" type="date" column="lastControlDate" />

    <many-to-one name="company" class="fr.model.company.Company" column="idCompany"
     not-null="true" />
    <many-to-one name="manufacturer" class="fr.model.component.Manufacturer"
             column="idManufacturer" not-null="true" />    

  </class>
</hibernate-mapping>

and the Manufacturer class:

public class Manufacturer implements Comparable<Manufacturer> {

private Long idManufacturer;
private String name;

I keep getting the association unmapped references error but I can't figure out why so far.

Edit: Manufacturer mapping -

    <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hib