[PHP] Notice: Undefined index: .... ???? wtf???

[KtK]

<?php
...
// tady uz to psat nebude
if &#40; array_key_exists&#40;'nick', $_SESSION &#41; &#41; &#123;
  if &#40;&#40;$_SESSION&#91;'nick'&#93; == "jirina"&#41; || &#40;$_SESSION&#91;'nick'&#93; == "bozena"&#41;&#41; &#123;
    body_admin&#40;&#41;; 
  &#125;
&#125;
body_right_two&#40;&#41;;
?>