My server has the following installed for MySQL:

[aly@shodan /home/aly]$ rpm -qa | grep mysql mysql-server-3.23.41-1 mysql-3.23.41-1 mysql-devel-3.23.41-1 <<<< As the other poster pointed out this may be missing mysqlclient9-3.23.22-6 php-mysql-4.0.6-15

So I wonder if you have missed one or some of the above packages for RH7.2,
plus do run ldconfig -v and check that it has picked up the shared lib. I mentioned the previous shell environment variables that you may have to tweak to get things to work. Good Night and HTH.

Cheers,

Aly.

"A good speech is like a good dress that's short enough to be interesting and long enough to cover the subject"