1.) Disable the "Download" button until at least one application is selected. After all you can not "Download" anything if you did not choose any applications. Duh!
2.) Please show download speed (perhaps text to download percentage).
3.) When a download fails you get "Unable to connect to the remote server" and then "Download aborted".
Not a very helpful error. Why not tell the user which one has failed? And perhaps ask user if user wishes to continue anyways.
Thus, it should be treated as a "warning" not an "error".
4.) Why download something if it has not changed since last