Hibernate Application: class not found?

I have an Hibernate application which worked til the last week. Now an
error:
Injection of resource dependencies failed; nested exception is
org.springframework.beans.factory.BeanCreationException: Error
creating bean with name 'mySessionFactory' defined in ServletContext
resource [/WEB-INF/spring/root-context.xml]: Invocation of init method
failed; nested exception is java.lang.NoClassDefFoundError: org/
hibernate/cfg/EJB3DTDEntityResolver at
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:
287)
On my local machine, it works. My classpath is ok.
Here's my configuration (Spring):
<bean id="myDataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName"
value="com.google.appengine.api.rdbms.AppEngineDriver" />
<property name="url" value="jdbc:google:rdbms://secret:secret/
secret" />
</bean>

<bean id="mySessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="myDataSource" />
<property name="annotatedClasses">
<list>
<value>it.trew.prove.model.beans.Scadenza</value>
<value>it.trew.prove.model.beans.Fornitore</value>
<value>it.trew.prove.model.beans.Societa</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</
prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">create</prop>
<!-- <prop key="hibernate.hbm2ddl.import_files">/setup.sql</prop>
-->
</props>
</property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager"
class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="mySessionFactory" />
</bean>

Please help!