Problem
You followed the guide http://oxpedia.org/wiki/index.php?title=AppSuite:DocumentViewer and updated to 7.4.1.
Now the document preview does not work any longer.
Solution
add the repository office-web and install the additional packages open-xchange-document-ui-viewer and open-xchange-documents-ui-static, see
updated documenation http://oxpedia.org/wiki/index.php?title=AppSuite:DocumentViewer
