I have been complaining about how trackbacks and pingbacks were not working after I upgraded from WordPress 2.6.5 to WordPress 2.7. The same problem cropped up when I upgraded to WordPress 2.8. Because of that issue, I was stuck with 2.6.5 for a while.
A few weeks back, when WordPress 2.8.4 was released, I tried my luck and upgraded to the latest version, yet again. At the same time I was anticipating the same problem with previous upgrades. To my surprise, trackbacks and pingbacks worked like a charm.
What I did was upgrade to the latest version from the Dashboard instead of downloading the compressed file from the WordPress website, unzipping it and then uploading to the server. That was what I usually did. Moreover, all that was needed in upgrading from the Dashboard was just one simple mouse click. I am a happy camper once again!