str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated

line #     FECES_ERROR_HANDLER('8192','str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated','/home/puke7/botb/whats/group/group_thread_class.php','24');

line #24     str_replace(array,'_','');
/home/puke7/botb/whats/group/group_thread_class.php

line #191     group_thread::Pop('18692');
/home/puke7/botb/kernel/_STACKMEM.php

line #181     STACK::FetchObject('group_thread','18692');
/home/puke7/botb/kernel/_STACKMEM.php

line #37     STACK::Fetch('group_thread','18692');
/home/puke7/botb/whats/group/group.php

line #93     require('/home/puke7/botb/whats/group/group.php');
/home/puke7/botb/whats/ajax/ajax_class.php

line #79     ajax::inHouse('/group/AjaxGroupThread/18692/botbr/915/');
/home/puke7/botb/whats/group/group_class.php

line #509     group::ReturnThread('18692','botbr','915');
/home/puke7/botb/whats/botbr/botbr.php

line #93     require('/home/puke7/botb/whats/botbr/botbr.php');
/home/puke7/botb/whats/ajax/ajax_class.php

line #200     ajax::inHouse('/botbr/AjaxProfile/915/');
/home/puke7/botb/whats/barracks/barracks.php

line #30     require_once('/home/puke7/botb/whats/barracks/barracks.php');
/home/puke7/botb/_FECES.php