White page problems after installation
 

I experience strange issues after install:

www.mydomain.com/forum and www.mydomain.com/blogs return 404 Not Found
www.mydomain.com/admincp returns blank page

HOWEVER when I try to access admincp at:

www.mydomain.com/core/admincp the logi page displays (but then, after login, it redirects back to www.mydomain.com/admincp, so it is not really usable). This trick does not work for forums or blogs.

My /config.php:

PHP Code:
$config['baseurl'] = 'http://www.mydomain.com';
$config['baseurl_core'] = 'http://www.mydomain.com/core';
$config['baseurl_login'] = $config['baseurl'];
$config['core_path'] = '/var/www/core';

The rest was left unchanged.

Any help would be appreciated.