Warning: require(/functions.php): failed to open stream: No such file or directory in on line 5

Fatal error: require(): Failed opening required '/functions.php' (include_path='C:\wwwroot\wiki.knebulae.com\vendor/pear/console_getopt;C:\wwwroot\wiki.knebulae.com\vendor/pear/mail;C:\wwwroot\wiki.knebulae.com\vendor/pear/mail_mime;C:\wwwroot\wiki.knebulae.com\vendor/pear/net_smtp;C:\wwwroot\wiki.knebulae.com\vendor/pear/net_socket;C:\wwwroot\wiki.knebulae.com\vendor/pear/pear-core-minimal/src;C:\wwwroot\wiki.knebulae.com\vendor/pear/pear_exception;.;C:\php\pear') in on line 5