Won't install Rated 1 out of 5 stars

Unfortunately, this add-on doesn't even install.
It complains about needing to change a necessary file, and not being able to do so.
There is no alternative way to install the add-on (I guess the problem is the "no restart" install which is obviously broken?) so I'll be looking for an alternative.

This review is for a previous version of the add-on (2.1.1-signed).