Rated 3 out of 5 stars

I'm also getting an XML error when attempting to change the settings of this Add-on :

- OS : SimplyMepis 7 ( Linux/Debian based distribution)
- TB version and revision : TB3.0
- Add-ons: Lightning 1.0-b1(pre), Mail Redirect 0.7.4 and Smart Template 0.4.0
- Situation error occurs
start TB -> Tools -> Add-ons -> select Smart Template -> Preferences -> displays xml error :

XML Parsing Error: undefined entity
Location: chrome://smarttemplate/content/settings.xul
Line Number 7, Column 1:

This review is for a previous version of the add-on (0.4.0). 

Thank you for the valuable information.
Fix bug at version 0.4.1.
It's foolish bug, wrong filename of locale dtd(linux case sensitive)...