Please note that the stability of the downloads is partly depending on the browser and / or virus scanner . We've currently experienced problems for Internet Explorer 9 in combination with e. g. AVG or McAfee. In these cases, the files are only partially downloaded or damaged. Unfortunately we cannot change this behaviour because there is not way of interacting with the browser. If you experience such problems, you should disable, at least for the period of the downloads, the virus scanner or use a different browser.