Error in Room Directory Discussion

I am using EP6 SP4.

If I try to access the discussion page within a room I obtain a NullPointerException.

I am longged on with a user with admin role and the discussion page within the personal documents works fine.

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java.lang.NullPointerException

at java.util.Hashtable.put(Hashtable.java:375)

at com.sapportals.wcm.repository.service.discussion.wcm.DiscussionAppPropertiesService.getAppPropService(DiscussionAppPropertiesService.java:42)

at com.sapportals.wcm.repository.service.discussion.wcm.Discussion.getNumberOfTopics(Discussion.java:552)

...........

com.sapportals.wcm.repository.ResourceException

at com.sapportals.wcm.repository.ResourceException.fillInStackTrace(ResourceException.java:401)

at java.lang.Throwable.(Throwable.java:85)

at java.lang.Exception.(Exception.java:33)

at com.sapportals.wcm.WcmException.(WcmException.java:107)

at com.sapportals.wcm.WcmException.(WcmException.java:103)

at com.sapportals.wcm.util.content.ContentException.(ContentException.java:46)

at com.sapportals.wcm.repository.ResourceException.(ResourceException.java:274)

at com.sapportals.wcm.repository.service.discussion.wcm.Discussion.getNumberOfTopics(Discussion.java:561)