In the latest Google Chrome v42 browser, a plugin setting is disabled by default. This setting blocks all Java applets (not only Fronter), and the Fronter OES. Fronter Java applets include the online application, multiple file upload and sound recorder. The Java tools fail to start, while editing a file will offer you the Webdav OES window instead of launching the plugin like on previous Chrome versions or other browsers.
The same issue is reported on Mozilla Firefox 37 also, but on Firefox you will just need to allow the relevant plugin to run. There is a “blocked” icon displayed informing you of a plugin requesting you to allow it to run.
Another issue reported on Chrome v42 is that in some installations PDF documents with Scandinavian characters fail to open. The workaround for this is to right click to download the file, or to disable the Chrome PDF viewer.
With respect to Java in particular, more information from Oracle is available here.