C.A.C. page crashes on view

See
http://confluence.atlassian.com/display/DOC/Redirect+users+straight+to+space+home+page+after+successful+login . It gives:

[ERROR] Mon Apr 25 21:40:36 CDT 2005 [com.atlassian.confluence.util.XWorkTransactionInterceptor] Invoking rollback for transaction on action '/pages/viewpage.action (ViewPageAction.execute())' due to throwable: java.lang.ClassCastException
Throwable:
java.lang.ClassCastException
at com.atlassian.confluence.renderer.UserMacroLibrary.getMacro(UserMacroLibrary.java:97)
at com.atlassian.renderer.v2.macro.DefaultMacroManager.getEnabledMacro(DefaultMacroManager.java:48)
at com.atlassian.renderer.v2.components.MacroRendererComponent.getMacroByName(MacroRendererComponent.java:177)
at com.atlassian.renderer.v2.components.MacroRendererComponent.handlePotentialMacro(MacroRendererComponent.java:95)
at com.atlassian.renderer.v2.components.MacroRendererComponent.render(MacroRendererComponent.java:74)
at com.atlassian.renderer.v2.V2Renderer.render(V2Renderer.java:38)
at com.atlassian.renderer.v2.V2RendererFacade.convertWikiToXHtml(V2RendererFacade.java:53)
at sun.reflect.GeneratedMethodAccessor78.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.springframework.aop.framework.AopProxyUtils.invokeJoinpointUsingReflection(AopProxyUtils.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:149)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:116)
at com.atlassian.confluence.util.profiling.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:16)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:138)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:152)
at $Proxy23.convertWikiToXHtml(Unknown Source)
at com.atlassian.confluence.pages.actions.ViewPageAction.execute(ViewPageAction.java:110)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)