This is not remotely like Down Them All. It is a match compared to a firestorm.
My point is not that this add-on is not good - this is simply not a good replacement for Down Them All, and you should not redirect to it.
Mozilla - you are great but this change that broke Firefox so the best add-ons no longer work is NOT OK!
You need to get Down Them All, Anti-Container, and Flash-got working again.
I don't care how you do it. You have to fix this.