Rated 5 out of 5 stars

Don't bother trying anything in "A possible solution" below...
None of the suggestions will work with this addon, it must be re-authored, and it doesn't look like that's going to happen.
I wish someone would write another add that could do what this
one did, STANDBY, HIBERNATE, or SHUTDOWN various computers/OSs when Firefox has finished with ALL downloads.

Darn... Rated 5 out of 5 stars

I tried to modify the .RDF and installed it, but it no longer functions at all. I'll really miss this one, it was very useful.

The developer's code is all pretty well documented throughout, but I just don't know enough about Firefox's internals to effect the necessary modifications. Someone who's well versed in Firefox's code, should be able to make quick work of it though.