The update RPMs have very strict version dependencies--you must have exactly the versions of the relevant RPMs installed that it wants. You've installed my upgraded PHP RPMs, which aren't what the update RPM wants to see. Your options are either to force installation of the older PHP RPMs, and give up the features of the newer version, or live with not having the update RPM installed (but having all the other packages).
AFAIK, my recent PHP RPMs contain all security patches, but of course I can't guarantee they aren't vulnerable to some exploit somewhere.
Bill, what I was referring to in my earlier message was the php-manual package. Previous versions of that one required the exact same version and release of PHP, which was silly. The latest one I've built requires PHP >= 4.0. For most purposes, though, it doesn't need to be installed at all, and it really wouldn't relate to the situation here.