使用memcached-session-manager后报错?报错

按照官网的文档安装了memcached之后，把memcached-session-manager-1.9.2.jar、memcached-session-manager-tc7-1.9.2.jar、spymemcached-2.11.1.jar三个jar包放到tomcat下面之后。用的是java序列化。配置如下

    <Manager className="de.javakaffee.web.msm.MemcachedBackupSessionManager"
    memcachedNodes="n1:127.0.0.1:11211"
    sticky="false"
    requestUriIgnorePattern= ".*\.(png|gif|jpg|css|js)$"
    transcoderFactoryClass="de.javakaffee.web.msm.JavaSerializationTranscoderFactory"
    />

然后一点进项目就报错，启动tomcat的时候没报错。一访问项目就报错。有没有懂的朋友帮忙看看什么原因啊。de.javakaffee.web.msm.MemcachedBackupSession.getAttributesFiltered这个类在memcached-session-manager-1.9.2.jar里面有啊，方法也有。为什么会报这个错误呢？

SEVERE: Error processing request

java.lang.NoSuchFieldError: attributes
        at de.javakaffee.web.msm.MemcachedBackupSession.getAttributesFiltered(MemcachedBackupSession.java:515)
        at de.javakaffee.web.msm.BackupSessionTask.call(BackupSessionTask.java:109)
        at de.javakaffee.web.msm.BackupSessionTask.call(BackupSessionTask.java:51)
        at de.javakaffee.web.msm.BackupSessionService$SynchronousExecutorService.submit(BackupSessionService.java:346)
        at de.javakaffee.web.msm.BackupSessionService.backupSession(BackupSessionService.java:205)
        at de.javakaffee.web.msm.MemcachedSessionService.backupSession(MemcachedSessionService.java:1030)
        at de.javakaffee.web.msm.RequestTrackingHostValve.backupSession(RequestTrackingHostValve.java:230)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:159)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:124)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:124)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:124)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:124)
        at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:124)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
        at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)