PHPfox expert needed ( site not loading due to class error)

After site migration to new server, they are not loading and error comes
" class Phpfox_Plugin" not found in /public_html/site/include/library/phpfox/phpfox/phpfox.class.php
(Check image)
checked the class file ...cant seem to fix the issue

....anybody with experience in phpfox can please assist .....only anyone with prior experience of PHPfox may please bid