I use Jaksta 1.5.1 (205), and all the older downloads seems to be deleted. List (everything) is empty.
And it is impossible to download new files from any sites. "Error Downloading" or no information and size
If you haven't already, start by trying a reinstall of Jaksta as that will reset all of the operations and preferences. If there is a break somewhere in its processing, restarting it fresh will give you a clean build that short work properly again.
Start with that and let us know if the problem continues.