paul.luminos.nl

This puzzled me for a bit: I downloaded the latest version of PHP for Windows, 5.3.0 non-thread-safe (NTS). Since PHP is only running in a single process, I thought I'd grab the faster non-threaded version.

As a result, many of my modules stopped loading, including php_gd, php_mysql and php_openssl, extensions you really can't live without.

I only really noticed the problem when all my locally hosted sites reported "DB Error: extension not found." Looking in Apache's error.log, the problem was revealed:

Warning:  PHP Startup: mysql: Unable to initialize module
Module compiled with module API=20090626, debug=0, thread-safety=0
PHP    compiled with module API=20060613, debug=0, thread-safety=1
These options need to match
 in Unknown on line 0

The moral of this story: save yourself the headache. Download the thread-safe PHP binaries instead.