PHP Code:
$categories_names_array[$lang['id']] = mb_split(preg_quote($categories_delimiter), $items[$filelayout['v_categories_name_' . $lang['id']]]); 
This also worked for me. Looks like a great solution

@mesnitu: It was always intended to make the category delimiter customizable in the config area, but issues like these got in the way.
Also note that EP4 is the only easypopulate version that actually supported multilingual categories. I was quite proud of that.