Translatio won't work

Hi there. Ik have done all the language setting. Installed the Dutch language, made the right settings in Extensions > Language and my entire website is in Dutch. I've installed the Dutch package in Easyblog and switched all the posts to Dutch. But still it say 'Read More' in stead off 'Lees meer' in my posts. What am I doing wrong here? And I want to make the language permanent so that my client always uses the right language. How do I do that? Greetings, Boris