Warning: require(./includes/startup.php): Failed to open stream: No such file or directory in C:\SERVER\data\htdocs\common.php on line 23

Fatal error: Uncaught Error: Failed opening required './includes/startup.php' (include_path='.;C:\php\pear') in C:\SERVER\data\htdocs\common.php:23 Stack trace: #0 C:\SERVER\data\htdocs\viewtopic.php(20): include() #1 {main} thrown in C:\SERVER\data\htdocs\common.php on line 23