Unfortunately, such a problem has many potential causes. Queue management, connection caps, disk cache, Java heap size limits, limitations of the underlying file system and/or storage, antivirus, firewall or router interfering or giving out... what I can assure you is that under normal circumstances, this has no reason to happen on a well-seeded torrent and you shouldn't need to restart torrents manually. Enabling console logging and checking the messages generated right after a download stalls could give some clues.
Although a look at those screenshots reveals you aren't using the latest version of the mod (2.5.0.0, newest is
3.5.0.0) and appear to be downloading to a Western Digital external disk ("F:\ElementsWD..."), so I recommend updating the mod and reading
http://www.sb-innovation.de/showthread.php?t=30949 before doing anything else.