In the past, i have been upgrading my PHP version on both of my Windows and Linux system. In Linux, i didn't encounter any problem, but in the other hand, Windows version stopped working since 5.2.7 on my system. This forced me to use the old 5.2.6 which was still working until 5.2.9 came yesterday. I tried to upgrade to 5.2.9 and the installer is now working again.
Thanks to the PHP team who have done better work on Windows installer this time. Let's hope they won't break it again in the next release