I wonder if you have come across the same problem that I have on WinVista/Apache2/PHP5:

I set my PHP ini settings in httpd.conf (either in the vhost or on a per-directory basis), so that each site can have its own settings, and the whole server be locked down easily without having to modify php.ini at all.

I’ve found however, that on Vista, periodically, the include_path value just gets forgotten about, and I have restart from the start menu with right-click > ‘Run as administrator’. After restarting, the include_path setting is then correct again, and the site functions fine.

(Having diffed a phpinfo() output page before and after this problem, I see the only changes are the Local Value for include_path, mbstring.internal_encoding and HTTP headers > Keep-Alive.)

Have you come across this? I’m baffled.. it’s as if it just forgets the setting after a while, and I can’t think why this is happening.