会话未通过文件传递正确的值

I am going crazy and need some tips and help. Working with custom cms and php programming language. I am working on online site on server.

Problem is next:

Session start is ok, In functions.php I start session['lng'] and put _LNG constant in it and it's ok, passing alright.

When I call session['lng'] in my other files I always get the same language constant (en) but I am passing (hr) or (de)?? I checked 10 time if session is set somewhere else but it isn't.

How can I check where's the problem...I really don't know what to do next

Did you place this at the start of other files before accessing session variables. It's required to access session vars.

<?php
session_start();