There are several different causes for that error. If the link you have for the source is no longer responding after you refreshed your sources you will get that error. The item will be in the list of available software yet the site it is located on is no longer reachable so you get a download failed error. If you have something in the queue to be downloaded and that particular program has a problem and then you try to download anything else you will get that error. First, refresh your sources again, then go to download something and make sure that you clear your queue first and then try downloading. When I get that error, I clear my queue, refresh the sources and then download and install something off one of the main sites just to make sure that the problem is not my phone. Then I go online on my desktop to www.iappcat.com and look to see what other sources have the program I had the problem with the first time and add that source to get the program.