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There is no reason to use an obsolete Red Hat release (5.2 is from 2008). Once you pay for a subscription with Red Hat you will be able to download and install the current release. If you don't want to pay then use CentOS for free, it is the same thing except you don't have to pay.
Using outdated Red Hat without a license won't help you learn Linux, it will teach you frustration.
Unless you have a specific need to learn Red Hat (they've asked you to be a server admin at work?) you might be better off with a free, general-purpose distro designed for desktop/laptop/netbook, like Ubuntu, Mint, etc.