From Aaron Cowell: "
Here's a new error for you, sorry I don't recall exactly what I did to generate this error. I was viewing blogs, was trying to see how to get to RSS feeds in blogs and switched blogs to world readable. Not sure if they are related.

Checking user module for updates.
Add: FAILED adding '' , moodle instance id = , Error: Column 'docid' cannot be null
exception 'dml_write_exception' with message 'Error writing to database' in /var/www/moodle/lib/dml/moodle_database.php:394
Stack trace:
#0 /var/www/moodle/lib/dml/mysqli_native_moodle_database.php(816): moodle_database->query_end(false)
#1 /var/www/moodle/lib/dml/mysqli_native_moodle_database.php(858): mysqli_native_moodle_database->insert_record_raw('block_search_do...', Array, true, false)
#2 /var/www/moodle/search/indexlib.php(244): mysqli_native_moodle_database->insert_record('block_search_do...', Object(stdClass))
#3 /var/www/moodle/search/update.php(143): IndexDBControl->addDocument(Object(UserPostSearchDocument))
#4 /var/www/moodle/search/cron_php5.php(22): require_once('/var/www/moodle...')
#5 /var/www/moodle/search/cron.php(25): include('/var/www/moodle...')
#6 /var/www/moodle/blocks/search/block_search.php(73): include('/var/www/moodle...')
#7 /var/www/moodle/lib/cronlib.php(116): block_search->cron()
#8 /var/www/moodle/admin/cron.php(91): cron_run()
#9

Finished user.

Finished 1 updates
"