Update to 3.3.2, comments broke

You might want to try deactivating all your plugins and see if that error goes away. If it does, then reactivate them one by one to find out which plugin is causing the error.

If it’s not the plugin, then try switching to the default twenty eleven theme. If the error goes away, then you’ll need to fix your theme.

If it’s not that, I would try re-installing WordPress again. Perhaps there was a glitch the first time.

Thank you for the suggestions Christine.

I tried what you suggested and it made no difference.

I decided to make a backup of the DB, removed the wp install, dropped all tables, and did a clean install. But for some reason we are still getting the same error on loading comments.
As you can see here: https://www.thevesuviusgroup.com/?p=1#comments

If I try to edit a comment I can see the comment though.

We are running Mysql 5.0.45 and PHP 5.2.9

Reading these posts:
https://www.bigboylemonade.com/pcre-version-problem-on-cpanel
https://labs.sasslantis.ee/2011/05/errors-in-wordpress-after-php-upgrade/
https://stackoverflow.com/questions/9323228/phpinfo-is-reporting-incorrect-pcre-version

These posts seem to suggest that the PCRE module could be the cause.

php reports that we use:

PCRE (Perl Compatible Regular Expressions) Support enabled
PCRE Library Version 4.4 21-August-2003

That’s kinda a old version, but should that give these errors?

The above posts suggest that either php is not referencing the right version, and Apache might just need proper restart. Or we just need a newer version installed.