My b2evolution Version: Attempting to install 2.4.2

Warning: main(antispam/_antispam.funcs.php) [function.main]: failed to open stream: No such file or directory in /home/curriers/public_html/danielpcurrier.com/inc/_misc/_misc.funcs.php on line 53

Fatal error: main() [function.require]: Failed opening required 'antispam/_antispam.funcs.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/curriers/public_html/danielpcurrier.com/inc/_misc/_misc.funcs.php on line 53

I notice all of these paths start with $model_path but I cannot find anywhere where this variable is set. What is $model_path and how is it defined?