I've had this same problem with filekicker in the past. Apparently, filekicker gets some badware uploaded on their site and are added to the black list. Wait a day, sometimes even in an hour or so, and when the badware gets removed you'll be allowed back in. Filekicker also gets overloaded and your downloads will keep getting kicked off with a "Server Busy" result
When this happens, use the secondary url that gets the file directly from Avant (or wherever they have it stored)