Arkadaşlar vbulletin kurulumda aşağıdaki hatayı alıyorum.(www.domainim.com/forum altına kuruyorum ve config.php'yi de editlemiştim)

Warning: require_once() [function.require-once]: Unable to access ./installcore.php in /home/public_html/forum/install/install.php on line 59

Warning: require_once(./installcore.php) [function.require-once]: failed to open stream: No such file or directory in /home/public_html/forum/install/install.php on line 59

Fatal error: require_once() [function.require]: Failed opening required './installcore.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/public_html/forum/install/install.php on line 59