how do i convert streaming for-pay video into video files?

All i seem to read about regarding downloading streaming video into video files discusses sites that are FREE like youtube or pornotube, daily motion, myspace, etc.
i want to save streaming video into permanent files off sites i pay for, but doesnt download FILES, just streaming...
even Replay seems to only do free stuff...
when i go to sites that are supposed to help- like this
"rtmpdump ( Freeware / Mac OS X, Linux, Windows ) is a console application that allows you to download RTMP and RTMPE streams to your hard drive. rtmpdump supports SWF verification. It can resume recording ( --resume option)
Example of usage:
rtmpdump -r "rtmp://host/dir/file.flv" -o filename.flv
If you see the following the "WARNING: Download may be incomplete, try --resume!" message, try to use the --resume option:
rtmpdump -r "rtmp://host/dir/file.flv" -o filename.flv --resume"

i have no idea what this means?
can someone explain to me in english...?