What need to do for supporting a new extension?

I use Ubuntu 9.10,PHP 5.3.1,apache2.24 I compiled the PHP from php source successfully. Now I want to build the mbstring module from source. My operations: shell> cd php src dir/ shell> phpize shell> .configure shell> make && sudo make install shell> echo ectension=mbstring.so >> php.ini Now it has built the mbstring.so. But my php still did not support this module. I found something in the log files of Apache Httpd server. "PHP Startup: mbstring: Unable to initialize module 51 Module compiled with module API=20060613 52 PHP compiled with module API=20090626 53 These options need to match " It seems so strange: why the module APIS are different when I build the PHP and PHP modules from the same php source tar file. another question: If I want to increase a dynamic module for PHP, What do I need to do? 1.setting the php.ini file 2.move the *.so files to the specified directory(extension_dir) 3.move the related headers to include directory( is this necessary?) is this enough for finishing that task( to support a module)? -- Best Wishes, Joewan