Why would Drupal 6.14 serve ano cached pages to a logged in user?

I requested a new password for testuser. Responded to the email sent by Drupal. Logged in. Changed my password. Went to the front page and it loaded like I was an anonymous user. Hit login tab and received access denied warning.

I have a lot of modules. I thought it had to do with phpBB integration. I read in the issue queue for that module that other people where having similar problems. So I removed that module and deleted the forum from the server. The problem persisted but not any where as close to as bad, so it is much better.

I had the forum install without a problem for a few days, before I forwarded the DNS to this particular installation of the site.

I do not use Boost or any other caching system than in the admin performance. That is set to Normal/5 min Minimum/ page compression enabled / block cache enabled / css and js optimized.

The Columns section front page uses panels and I set them to cached.The Events page uses panels and I have them set to cache too.

I went through and set all the views time-based cache to one hour with the exception of a couple blocks that should be dynamic.

With the exception of the caching and installing phpbb3 (and a ton of theming) the site is the same as on the other server where it ran fine since I published it almost one month ago.

Are there an threads about this type of problem that do not have to do with the boost module and other aggressive caching devises?

Should I try to revert all the core files from a backup because they might have been corrupted at some point? I checked the database tables to compare them to the installation that worked and the fields are the same. I went through all the variable_get() in bootstrap.inc and none exists in the database table so it uses the default values. I also check when the files were updated and almost all of the folders and file have not been change since I installed the site on the new VPS.

I'm at a loss.