You don't have a Red Hat subscription or simply no internet connection to connect to the NRH, yet you have the installation DVD that contains all the packages you need!
You can install an httpd server, then put the "Server" folder from the DVD to use as a remote yum DVD repository. Here's an example of client-side configuration:
http://server/repositories/rhws/5Client/i386/repodata/primary.xml.gz: [Errno -3] Error performing checksum
Trying other mirror.
Error: failure: repodata/primary.xml.gz from dvd-base: [Errno 256] No more mirrors to try.
It's probably because you're running the createrepo command without the necessary arguments for Red Hat 5. Brief explanation:
Because RPM packages for Red Hat Enterprise Linux 6 are compressed using the XZ lossless data compression format, and may also be signed using alternative (and stronger) hash algorithms such as
SHA-256, it is not possible to run createrepo on Red Hat Enterprise Linux 5 to create the package metadata for Red Hat Enterprise Linux 6 packages.
The createrepo command relies on rpm to open and inspect the packages, and rpm on Red Hat Enterprise Linux 5 is not able to open the improved Red Hat Enterprise Linux 6 RPM package format.