Rated 5 out of 5 stars

Im still testing this addon and I have a question: Does this add-on to protect me from trojans and viruses that steal passwords from the Firefox profile or from the Firefox directory on HDD?

This review is for a previous version of the add-on (1.15.4.1-signed). 

No, it doesn't. However if you set strong enough master password, then even if someone steals your profile, without that password they wont be able see or even use stored passwords and other encrypted data.