Upgrading Drupal

I just upgraded one of my sites to Drupal 5.2 - and had a few problems with the image module along the way, no idea if that is relevant. Since then I get the following error message appearing from time to time:

warning: Invalid argument supplied for foreach() in /home/gmpmprdg/public_html/500/includes/file.inc on line 551.

This seems to happen systematically when I click on the "read more" to display the full node from the teaser.

I recently tried to upgrade my site from 5.2 to 5.3 and after the upgrade essentially all the "node" pages do not show but instead I get an error about a string array issue in theme.inc on line 555.

The front page loads fine, the forums load fine until you read a post, the admin pages all work, all the cck nodes works, and - more importantly, everything worked in 5.2.

I've done this on a devel version of my live site, so for now I'm still at 5.2 on my live site.

I get this error when running the update script. I am doing a test fresh install from the old database. Any ideas?

Updating Error

An unrecoverable error has occured. You can find the error message below. It is advised to copy it to the clipboard for reference. Please continue to the update summary
An HTTP error 406 occured. update.php?op=do_update

Update Summary

We have about 30 sites under one multisite environment to upgrade. Do I need to concurrently log in to every site and then do the steps explained in upgrade.txt????

I posted this even in General discussion, sorry for that. i think this is the right place.

Hi all,
I just upgraded my website from version 4.7.2 to 4.7.8. Now I've done that, i cannot access to my the website anymore.
When I want to access as user admin with the correct password and push the submit putton nothing happens. If I, for example,
enter a wrong password the entry mask says me, I've entered a wrong password.

I even checked the password in the database (MD5), it is still correct.

Does someone has suggestions?

Do all 5.2 contib modules have to be ported to 5.3, or should they work with 5.3. I have lots of contrib modules running on a 5.2 site and wonder if they will continue to work with 5.3.

Thanks!