ran git pull on moodle core on branch origin/master to version "2011101900.01" 2.2dev (build: 20111019) and went to login and install the updates and received a blank page. I enabled debugging in config.php and saw the above error.

I ran php upgrade.php and the updates installed successfully, but the error still remains. The error also shows for /admin/index.php (with its respective path) and for /login/index.php (with respective path). More info in thread: http://moodle.org/mod/forum/discuss.php?d=188664

Fatal error: Class 'context' not found in /var/www/school.tiseagles.com/htdocs/moodle/lib/accesslib.php on line 4440 Call Stack: 0.0004 662080 1.

() /var/www/school.tiseagles.com/htdocs/moodle/index.php:0 0.0017 676096 2. require_once('/var/www/school.tiseagles.com/htdocs/moodle/config.php') /var/www/school.tiseagles.com/htdocs/moodle/index.php:31 0.0019 683152 3. require_once('/var/www/school.tiseagles.com/htdocs/moodle/lib/setup.php') /var/www/school.tiseagles.com/htdocs/moodle/config.php:433 0.0204 3436304 4. require_once('/var/www/school.tiseagles.com/htdocs/moodle/lib/accesslib.php') /var/www/school.tiseagles.com/htdocs/moodle/lib/setup.php:437