The typical cause of this error is that your Webserver is running PHP in “CGI” mode, and Jamroom needs to have the user permission set correctly for this mode. You’ll want to edit the jamroom/config/settings.cfg.php file and change the following:
$config['directory_mode'] = 0777;
$config['file_mode'] = 0666;
$config['directory_mode'] = 0755;
$config['file_mode'] = 0644;
After making this change you will want to Regenerate your Artist / Member Pages from the Admin Menu → Tools Menu.
If this does not fix the problem, you’ll likely need to get assistance from your web hosting provider, as the error can be caused by many different server-related issues. You can often consult your Web server error log for further information to the cause of the problem.