why the oscahcetest.jsp in oscache example can not run

I run the oscahcetest.jsp on weblogic6.1, Then got the error:
 
[INFO] Config - -Properties {cache.capacity=1000}
[INFO] ServletCacheAdministrator - -Constructed ServletCacheAdministrator()
[INFO] ServletCacheAdministrator - -Created new instance of
ServletCacheAdminist
rator
[INFO] ServletCacheAdministrator - -Created new application-scoped cache at
key:
 __oscache_cache
[INFO] ServletCacheAdministrator - -Created new cache in scope 4
[WARN] LRUCache - -When using the LRUCache under JRE 1.3.x,
commons-collections.
jar should be added to your classpath to increase OSCache's performance.
<2003-12-10 下午05时04分46秒> <Error> <HTTP> <[WebAppServletContext(2422742,
IQS,
/IQS)] Servlet failed with Exception
java.lang.NoSuchMethodError
        at
com.opensymphony.oscache.web.ServletCacheAdministrator.getCache(Servl
etCacheAdministrator.java:220)
        at
com.opensymphony.oscache.web.tag.CacheTag.doStartTag(CacheTag.java:44
4)
        at jsp_servlet._jsp.__cachetest._jspService(__cachetest.java:132)
        at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
        at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:262)
        at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:321)
        at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:198)
        at
weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppSe
rvletContext.java:2637)
        at
weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestIm
pl.java:2359)
        at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
        at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)

What's wrong?