Drupal display blank page after adding or enabling new Drupal modules.

Page access control not found or Drupal display blank page after you adding or enabling new Drupal modules.  The example that I get, gallery2 just display blank page. The reason is that you may be running out of memory, you may need to check the PHP configuration file and check default memory setting for your PHP.
 

The default PHP memory limits for:
Fedora Core 5: 8M
Fedora Core 6: 16M

Solution: increase PHP memory by editing the PHP configuration file located at /etc/php.ini or use find command to locate the PHP (php.ini) configuration files.
[root@fedora ~]# find / -name php.ini