Rated 1 out of 5 stars

Use Go To Parent Folder instead. It is up to date, works great and compatible with FF 3.5-3.7

https://addons.mozilla.org/en-US/firefox/addon/7377/


A nice complement to this is Show Parent Folder
https://addons.mozilla.org/en-US/firefox/addon/7372/
FF 3.0-3.7