Drush can't update core 6.22 to 6.24 but claims success anyway

I am in the /home/[accountname]/drupal6/sites/sitename.org directory and run drush up.

I get this:

$ drush up
Refreshing update status information ...
Done.
Update information last refreshed: Fri, 2012-02-03 16:26

Update status information on all installed and enabled Drupal projects:
 Name               Install  Proposed  Status
                    ed       version
                    version
 Administration     6.x-1.8  6.x-1.8   Up to date
 menu
 Admin block        6.x-1.3  6.x-1.3   Up to date
 Automatic          6.x-1.2  6.x-1.2   Up to date
 Nodetitles
 Drupal core        6.22     6.24      SECURITY UPDATE available
 Comment notify     6.x-1.6  6.x-1.6   Up to date
 Computed Field     6.x-1.0  6.x-1.0-  Up to date
                    -beta5   beta5
 Content Templates  6.x-1.2  6.x-1.2   Up to date
 (Contemplate)
 Content            6.x-2.9  6.x-2.9   Up to date
 Construction Kit
 (CCK)
 Date               6.x-2.8  6.x-2.8   Up to date
 DHTML Menu         6.x-3.5  6.x-3.5   Up to date
 Global Redirect    6.x-1.4  6.x-1.4   Up to date
 Google Analytics   6.x-3.3  6.x-3.3   Up to date
 Term lower name    6.x-1.1  6.x-1.1   Up to date
 Menu block         6.x-2.4  6.x-2.4   Up to date
 Mollom             6.x-1.1  6.x-1.16  Up to date
                    6
 Pathauto           6.x-1.6  6.x-1.6   Up to date
 Poormanscron       6.x-2.2  6.x-2.2   Up to date
 Table of Contents  6.x-3.7  6.x-3.7   Up to date
 Token              6.x-1.1  6.x-1.18  Up to date
                    8
 Update status      6.x-1.1  6.x-1.1   Up to date
 advanced settings
 Upgrade Status     6.x-1.1  6.x-1.1   Up to date
 Views              6.x-2.1  6.x-2.16  Up to date
                    6
 Wysiwyg            6.x-2.4  6.x-2.4   Up to date


Code updates will be made to drupal core.
WARNING:  Updating core will discard any modifications made to Drupal core files, most noteworthy among these are .htaccess and robots.txt.  If you have made any modifications to these files, please back them up before updating so that you can re-create your modifications in the updated version of the file.
Note: Updating core can potentially break your site. It is NOT recommended to update production sites without prior testing.

Do you really want to continue? (y/n): y
Source directory /home/[accountname]/drupal6/drupal6 is not readable or [error]
does not exist.
Project drupal was updated successfully. Installed version is now 6.24.
Backups were saved into the directory                                [ok]
/home/[accountname]/drush-backups/rpt_prod/20120203222553/drupal.
Backups were restored successfully.                                  [ok]

The weird thing is there is no such directory /home/[accountname]/drupal6/drupal6. I have no idea why Drush is looking for it.

I checked admin/reports/status afterwards, and it was not updated to 6.24. It's still on 6.22.