When I use the "add-on" Download Helper icon to select a video file (FLV) for download, I'm asked which folder it should go into (as usual). But when I click "Download," the file never appears to start downloading. The number in parentheses next to the icon indicates that one file is in the queue, but in right-clicking and then checking the download queue, no files are listed. And then it sits in that configuration forever. No file ever appears anywhere on my system. The destination folder is present and accessible. This was a sudden change as of this morning, with no updates to any of my software or apps. I tried refreshing Firefox (v. 36), and I've tried disabling/deleting/reinstalling Download Helper (version 4.9.24) with absolutely no change in these circumstances. It does me no good to open Firefox in safe mode, since then Download Helper isn't enabled and therefore is untestable. Any ideas?