Code:
rtmpdump -r "rtmpe://46.246.124.25:1935/live/" -a "live/" -f "WIN 16,0,0,235" -W "http://prvservers.com/j/jwplayer.flash.swf" -p "http://prvservers.com/embed2.php?u=cnnn&vw=658&vh=450&domain=usachannels.tv" --live -y "cnnn" -T "#yw%tt#w@kku" -o "cnnn.flv"
try -T with two %% if it doesn't works