In TS I've recognized a typo in German translation for the Activity
"USER XXX previewed document XXXX."
I've checked it in my Alfresco 5.0 demo environment and there it is the same.
The current German translation is
"USER XXX hat eine Vorschauf auf Dokument YYY angezeigt in SITE ZZZ"
The word "Vorschauf" is miss spelled and has to be "Vorschau" without the F at the end. "Vorschau" means "preview" in English. A word "Vorschauf" does not exist in German.