Download it here at http://www.ttcsweb.org/ttcsosswincd.torrent . This redirects to the Chip.de webpage about the TTCS OSSWIN CD.
Click on the download link button
This will take you to a page listing download options. There is usually only one download option :
Click on that and the torrent download in your preferred BitTorrent client should start automatically (or your browser will prompt you on what to do with the .torrent file)