Upgrading Drupal

I hope someone can advise me what to try next.

I am upgrading from Drupal 5 to 6. I edited settings.php per the instructions and tried to run update.php, but got a blank screen. However, it must have done something, because I'm getting less error messages (the first ones, at the end of this message had to do with the database, primarily).

Can anyone advise as to what I might try next?

Here are the current error messages when I try to log in with http://psychinnovations.com/psych/?q=user while Drupal is offline:

Warning: include_once(./includes/module.inc) [function.include-once]: failed to open stream: No such file or directory in /home/bobsterz/public_html/psych/install.php on line 36

Warning: include_once() [function.include]: Failed opening './includes/module.inc' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/bobsterz/public_html/psych/install.php on line 36

Fatal error: Call to undefined function module_list() in /home/bobsterz/public_html/psych/install.php on line 39

==== this text was my first post, and it shows that a had different error messages before I got the right settings.php file in place ===

My attempt at upgrading has hit a snag with the update.php process (or maybe it's worse than that and update.php won't help, but I don’t know).

Hey I just upgraded to the lastes version of 6.x and got these weird errors.

I did also install a lot of modules, could that be it? Where do I start? Appreciate any input... thanks

I'm not running 6.17 so that COULD be it - but I don't see Split Summary at Cursor above my node body editor. In fact I don't really remember it ever - I've only seen it on THIS forum.

Any chance I can display picture smaller in the teaser and have them at another size when you actually open the post? Thanks!

We have multiple copies of one Drupal web site. A couple are for kicking around and beating the crap out of. One is sort of a test/staging environment, where we make content changes. Meanwhile, the live site chugs along. Every now and then, when it's time to roll out an update, what we do is update Drupal and/or modules on the test/staging server. Then, we dump out a bunch of tables from the production server, so we keep new users, uploads, etc.

I am upgrading from 6.16 to 6.17. I followed the directions in upgrade.txt as well as watched this tutorial video

http://learnbythedrop.com/drop/70

I disabled contributed modules, deleted everything in the drupal directory, uploaded the new drupal files, then uploaded my backed up /sites folder.
Went to mysite.com/update.php and ran the updates successfully.