I read the thread.
I did exactly all steps.
I added a Greek.php file to language folder. In this php file, i modified the code so it would be like this at the beggining
$LangLocal = array('lang_code'=>'el-GR', 'title'=>'Greek');
I also added to every language file this code
$constLang = array('const'=>'_BOOKLIBRARY_LANGUAGE_GR', 'value_const'=>'Greek');
I also added greek language to joomla. That gives me other problems, but anyway i did that too.
The component wont get translated.
I can see the greek entries at component language manager, but the value is not the one i set. Sometimes when i changed something to the php file, i couldnt find it at language manager.
I dont know what else to do.