Cözümü bulamadim hatam nerede

DOSYA: /VAR/WWW/VHOSTS/Siteadi.com/HTTPDOCS/APPLİCATİON/VİEWS/FRONT/İNCLUDES/HEADER.PHP
SATIR: 8
İŞLEV: _ERROR_HANDLER

8. Satir kodu

<a class="menuBtn trimUser user-button <?php echo isset($this->session->user)?'active':"";?>" <?php echo !isset($this->session->user)?'data-toggle="modal" data-target="#addPortfolioModal"':"";?>><?php $username=$this->session->user['name'];$subUser=substr($username,0,1);