It seems that several folks have had issues with FF & the download manager. Not sure what it is, but I just killed it and I'm going back to HTTP. Others also mentioned that I should only do 2 at a time, which I recall trying to do more than 2 downloads would hang up IE as well. Thanks,
We've successfully used other download managers such as ReGet to manage and restart the downloads as needed. Just need to make sure the program you use will let you enter you username and password as the download link is secured.