maintenance mode after error occurs while running update Error occurs While I'm running update for my drupal site.  And it stuck in maintenance mode.
I can't log in to it using /user/login.

I changed $update_free_access = TRUE in settings.php and run update.php.
And I see this screen.


It says ctools module is missing.
How can I re-install module when I can't login as administrator?

[Edit]
In the hope of getting the module back, I restored the database with my backup sql-dump via phpmyadmin.
After that, it came to 500 internal server error.

I don't know what was wrong?
Is there any way I can restore my site back on?

Thanks in advanced!
Most housekeeping tasks like these can be done using Drush, a Drupal command line managing tool. For example, you can reinstall the module using 

drush pm-disable modulename
drush pm-uninstall modulename
drush pm-enable modulename


the database can be updated by issuing

drush updatedb


And code is easily updated with

drush pm-update


To use drush you need a shell access to a server your site runs on. No authorization as Drupal user is needed.