Linux 64-bit Prerequisites

I have a requirement to install the following two packages on Red Hat Enterprise 5 as a prerequisite for the installation of a software package:

compat-db-4.2.52-5.1 (i386)
compat-db-4.2.52-5.1 (x86_64)

The problem is when I install one of the packages (makes no difference which one) I cannot install the other package because it states it is already installed. But when I run the check to see what is installed it only lists the one package. How do I get around this so I can install both packages?

Forgive me but I am fairly new to the Linux world but am trying to become more proficient.