IIS Manager won't create user profile

Hello to everyone,

I am suspicious that after installing PHP 5.4 on IIS 8.5 / Windows 8 (via MS Web Platform Installer), IIS manager gave up creating user profile when I create a new site. Before this, when I create a site, IIS manager was creating a user profile under "c:\users\" directory for the site's application pool.

Because of this, I receive "503 service unavailable" message.
When I check the site's application pool status in IIS manager, I see that the pool seems to be stopped.
Restarting it doesn't help.
If I set the site's application pool to any other application pool which has a user profile, the site works fine.

I checked logs by event viewer but I found nothing related to this situation.

Can you help me to solve this problem?

Thank you...