WordPress MU

I'm having a little trouble upgrading from WPMU 1.2.5a to 1.3. I've made some modifications to the 1.2 code so when 1.3 came out I switched to the new tag on my dev server, resolved all the conflicts, and it worked fine. But then when I copy that code to the live servers (preserving their .htaccess and wp-config.php) I get php errors. If I try to load the main blog I get:

PHP Fatal error: Call to undefined function update_object_term_cache() in /wp-includes/post.php on line 1774

If I try to load /wp-admin/upgrade.php I get:

PHP Fatal Error: Call to undefined function _http_build_query() in /wp-includes/functions.php on line 589

I've googled these errors and the only solutions offered have been to delete everything and start with a fresh copy of 1.3. Since I've customized mine I can't really do that though. Has anyone been able to find the cause of these errors yet?

No, and a lot of people are having issues upgrading.

Since you made customizations, you did take notes right? So you know what you changed? then you could just do a fresh copy and make those changes to the new code.

Might be less work than tracking down those errors. A load of stuff got moved around & dropped.

I could diff out my changes into a patch file but I'm not sure that would help (since it should diff the problem with it). What puzzles me is why it works perfectly fine on my dev server but none of my live servers. I'm using the same code and just swapping it in for the existing code. When it didn't work I just swapped back in the old code, no harm done.

Aha! Found the problem! One of the files I was keeping was wp-settings.php, but in 1.3 some new includes were added to it making the old one incompatible. If I discard the old wp-settings.php it works. That also explains why my dev server worked fine (since the changes to that file were merged in).

I had made a couple server-specific tweaks to wp-settings.php which is why I was keeping it. I also moved those tweaks to wp-config.php so I shouldn't have this problem anymore.

So in the end, the culprit was simply an old wp-settings.php.