tomcat集群求教
描述：
   公司之前的架构是jsf + hibernate+ spring 一个apache后面跟了5个tomcat。使用的是非粘性session，如今要改成粘性session即 session共享。 一直包错如下面这写信息,我在想这个和事务管理器有什么关系呢？ 关键是我将能序列化的都序列化了啊！！！

求大神回复 不甚感激！
   
下面是错误信息： 
[org.apache.catalina.ha.session.DeltaManager] - <Unable to serialize delta request for sessionid [59C455014A1C6AB2B6C43798D334AD67.tomcat1]>
java.io.NotSerializableException: org.springframework.orm.hibernate3.HibernateTransactionManager
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
        at java.io.ObjectOutputStream.writeArray(ObjectOutputStream.java:1251)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1075)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
        at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
        at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
        at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
     &nb