Upgrading Drupal

Ok, so starting with the process of updating one of my old sites I first updated from 5.7 to 5.12. That seemed to go over well, so tried to go another step and upgrade to 6.6. I'm then getting the following errors instead of any upgrading graphic.

I've disabled and uninstalled all contrib modules, and still get the same issue.

Warning: Unknown column 'serialized' in 'field list' query: SELECT data, created, headers, expire, serialized FROM cache WHERE cid = 'variables' in /var/www/rzbndbb.net/includes/database.mysql.inc on line 128

Warning: Unknown column 'serialized' in 'field list' query: UPDATE cache SET data = 'a:65:{s:13:\"filter_html_1\";i:1;s:18:\"node_options_forum\";a:1:{i:0;s:6:\"status\";}s:17:\"menu_primary_menu\";i:2;s:19:\"menu_secondary_menu\";i:2;s:15:\"install_profile\";s:7:\"default\";s:17:\"node_options_page\";a:1:{i:0;s:6:\"status\";}s:12:\"comment_page\";i:0;s:14:\"theme_settings\";a:20:{s:11:\"toggle_logo\";i:1;s:11:\"toggle_name\";i:1;s:13:\"toggle_slogan\";i:0;s:14:\"toggle_mission\";i:1;s:24:\"toggle_node_user_picture\";i:0;s:27:\"toggle_comment_user_picture\";i:0;s:13:\"toggle_search\";i:0;s:14:\"toggle_favicon\";i:1;s:21:\"toggle_node_info_blog\";i:1;s:22:\"toggle_node_info_image\";i:0;s:21:\"toggle_node_info_page\";i:0;s:22:\"toggle_node_info_story\";i:0;s:12:\"d in /var/www/rzbndbb.net/includes/database.mysql.inc on line 128

Hi
Thanks for the great video. I followed it and everything was O.K
But i didnt understood something.
When i remove the old files and replace then with the new files after that i have to copy my backup there. How to do this. When i pasted it there again , the new files which i put before been replaced.
So how does it exactly work.
I am so confused.

And Thanks again

I did do a search on forum and in documentation on this but found no help. Wish I could attach a screen shot to show what I'm talking about!

Here is what I am trying to do:

I run 2 Drupal 5.12 sites. The reason for this is that quite a few modules are still in dev being ported to 6x, but are not yet final.
I would like to create a corresponding 6x site in a subdirectory/subdomain like test.mydomain,com.

Hi,
I have searched the forum but i could not find any situation like mine. I have d5 installation on my windows pc. my conf is here: apache 2.0.63 and PHP 5.2.3 and mysql 5.

There are three sites on D5: mysite, copyOfMysite, testSite. My Drupal installation is under C:\www\drupal, by the way. So, C:\www\drupal\sites\mysite and so on. There is no problem with my installation. when i point to " mysite" with my explorer, i can reach mysite. No problem.

I'm trying to update my site from 6.5 to 6.6. I have backed up my files, followed the instructions in the UPGRADE.txt file, and run into the following.
When attempting to access update.php, I am forwarded to install.php as though the site wants to create a fresh installation. I am not given the option to upgrade. How do I fix this and complete the upgrade?