Rated 1 out of 5 stars

Not much detail instruction given. And finally:

Firefox could not install the file at

https://addons.mozilla.org/en-US/firefox/downloads/file/65444/bengali_bangladesh_dictionary-0.03a-fx+tb+sm.xpi

because: Unexpected installation error
Review the Error Console log for more details.
-203

This review is for a previous version of the add-on (0.03a).