Oh sorry, The official connector i download from this page.
http://dev.mysql.com/downloads/connector/php/
They are not the extentions coming with php zip package. The php.net connectors are also work fine for me.
Nowadays Mysql distribute the mysql/mysqli modules independently.Because the ones coming with php zip package do not support the complete functions of the latest MysqlDatabase(read the page i mentioned above for more details).
I read your message above, and see sth strange here:
/*
MysqlI Support | enabled
Client API library version | 5.0.22 (since I tried upgrading to mysql 5.0.22)
Client API header version | 4.1.7
*/
The client API relate to php_mysqli.dll seems working. But the client API header relate to libmysql.dll is the old one which coming with php zip package. I think your php didn't find the correct libmysql.dll(version 5.0.22). The right libmysql.dll is coming with the zip package you can download from the page i mentioned above. but i have doubt in checking their md5 checksums.