Greetings
Similar problem experienced by a few others:
1) Status report tells me to apply security updates
2) Backed up the system (thank the goddess!)
3) Followed the rest of the update instructions
4) After all the dust had settled, Status report tells me I'm still on 6.17
5) Repeat previous steps out of sheer bloody-mindedness
7) Read through the forums
Discovered that I, like some others here, have managed to get a "drupal-6.16" folder in my sites/all/modules folder. Like others I have no idea how the hell that got there.
Searched through the database and found the following in my system table:
SQL result
Host: localhost
Database: whicall7_which
Generation Time: Aug 17, 2010 at 10:51 PM
Generated by: phpMyAdmin 3.2.4 / MySQL 5.0.90-community
SQL query: SELECT filename, name, type, status FROM `system` ORDER BY `system`.`type` ASC LIMIT 0, 100 ;
Rows: 82
filename name type status
sites/all/modules/adsense/adsense.module adsense module 1
sites/all/modules/drupal-6.16/modules/system/system.module system module 1
sites/all/modules/drupal-6.16/modules/aggregator/aggregator.module aggregator module 0
sites/all/modules/drupal-6.16/modules/block/block.module block module 1
sites/all/modules/drupal-6.16/modules/blog/blog.module blog module 1
sites/all/modules/drupal-6.16/modules/blogapi/blogapi.module blogapi module 0