Problema com Spring: NotWritablePropertyException

public class RelatorioColetasBusiness implements IRelatorioColetasBusiness {

	private IManterColetaDAO coletaDAO;	
	private IManterColetaAgendaDAO coletaAgendaDAO;

	public void setColetaDAO(IManterColetaDAO coletaDAO) {
		this.coletaDAO = coletaDAO;
	}
	
	public void setColetaAgendaDAO(IManterColetaAgendaDAO coletaAgendaDAO) {
		this.coletaAgendaDAO = coletaAgendaDAO;
	}

//	public void getColetaAgendaDAO() {
//		return this.coletaAgendaDAO;
//	}
}

public abstract class ADaoSpring extends HibernateDaoSupport { ... }

public interface IManterColetaAgendaDAO { ... }
  -- public class ManterColetaAgendaDAO extends ADaoSpring implements IManterColetaAgendaDAO { ... }

public interface IManterColetaDAO { ... }
  -- public class ManterColetaDAO extends ADaoSpring implements IManterColetaDAO{ ... }

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
    "http://www.springframework.org/dtd/spring-beans.dtd">

<beans default-autowire="byName">
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		...
    </bean>
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
                ...
    </bean>
    <!-- Mapeamentos do hibernate -->
                ...
    <!-- /Mapeamentos do hibernate -->

    <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref bean="sessionFactory"/>
        </property>
    </bean>

    <bean id="coletaAgendaDAO" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" >
	<property name="target">
            <ref local="objAManterColetaAgendaDAO"/>
	</property>
        <property name="preInterceptors">
            <list>
                <ref bean="wbsaInterceptador"/>
            </list>
        </property>

        <property name="transactionManager">
            <ref bean="transactionManager"/>
        </property>
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED,-Exception</prop>
            </props>
        </property>
    </bean>

    <bean id="relatorioColetasBusiness" class="business.relatorio.impl.RelatorioColetasBusiness" singleton="true" autowire="no">
        <property name="coletaDAO">
            <ref local="objAManterColetaDAO"/>
        </property>
        <property name="coletaAgendaDAO">
            <ref local="objAManterColetaAgendaDAO"/>
        </property>			
    </bean>

    <bean id="objAManterColetaDAO" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target">
            <ref bean="manterColetaDAOTarget"/>
        </property>
        <property name="proxyInterfaces">
            <value>persistence.dao.interfaces.IManterColetaDAO</value>
        </property>
        <property name="interceptorNames">
            <list>
                <value>hibernateInterceptor</value>
            </list>
        </property>
    </bean>

    <bean id="objAManterColetaAgendaDAO" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target">
            <ref bean="manterColetaAgendaDAOTarget"/>
        </property>
        <property name="proxyInterfaces">
            <value>persistence.dao.interfaces.IManterColetaAgendaDAO</value>
        </property>
        <property name="interceptorNames">
            <list>
                <value>hibernateInterceptor</value>
            </list>
        </property>
    </bean>
    <bean id="manterColetaDAOTarget" class="persistence.dao.ManterColetaDAO" singleton="true"/>
    <bean id="manterColetaAgendaDAOTarget" class="persistence.dao.ManterColetaAgendaDAO" singleton="true"/>