Sorry for the delay.
Can you try this latest beta of Jaksta:
If it still doesn't work, the next time this occurs can you send the log file to us? You can find it by going to File|Reveal Log File... in the menu.
if i can help, this normally happen with streams that are protected. It is not a strong type of protection, but sometimes it is due to this.
The question is, Can you help?
I had a look at this website, and indeed they require a user login to watch movies. You may be able to download if you activate the 'http download' in the settings. It will record while you have the movie running. But if you stop watching the movie the recording will stop. Still, depending on the strongness of their security it may not work with Jaksta.
As tonkpils suggested, the "Anways Record HTTP" option in the Preferences is certainly worth a try.
Otherwise, send us the log file and we can probably tell you what the problem is. Streams that are just encrypted via HTTPS we should be able to handle, but most proprietary encryptions don't currently work.
I am trying to download this video: http://www.pbs.org/video/2365663085/
It's available to PBS subscribers. Jaksta (v 1.4.6) keeps announcing "Stream Added" but each stream is stopped by "Error Downloading" and then "Discarding."
Is there a way to download this video?