The safest thing you can do (I think) is to rebuild a php.src.rpm file. That way the php rpms will be made specific for you system and I believe it will be safe to install the rpms.
There are two ways to do it:
1. grab the php.src.rpm file, ex.
php-4.2.3:
http://www.atomicrocketturtle.com/psa/SRPM...4.2.3-1.src.rpm
php-4.3.0:
http://www.atomicrocketturtle.com/psa/SRPM...4.3.0-3.src.rpm
php-4.3.1:
http://www.atomicrocketturtle.com/psa/SRPM...4.3.1-1.src.rpm
when you have downloaded it you can run:
rpm -Uvh php_filename.src.rpm and then go into /usr/src/redhat/SPECS/ and there you can edit the php.spec file if you want to change the ./configure options. When you are satisfied with it you run: rpm -ba php.spec to make the rpms.
When this is done you can find them in /usr/src/redhat/RPMS
Then you just go to that dir and run rpm -Uvh *.rpm
2. If you don't want to edit the php.spec file you just run:
rpm --rebuild php_filename.src.rpm, go to /usr/src/redhat/RPMS and run rpm -Uvh *.rpm
BUT to work with .src.rpm files, you need to have alot of -devel rpms and a c++ compiler (I think that is what it is called)
I've got all this info from Atomicturtle in the plesk forum. AND he is one of the founderd ("the founder") of plesk and plesks rpm version... so.. more info can be found in the plesk forum (
http://forum.plesk.com) or ask NightHawk. He knows how this stuff work