We found out the frontend-language 500 error issue. We have fixed the issue and updated the script on Codecanyon. You will get notified via email when the update will available to download. Please download and use the updated script to get rid of the issue.
Our language system is fully dynamic. When you browse a page where has some custom text. The language system automatically adds the text to the language file. Please reload the page Language -> Frontend Language you will get the words to translate.