You've run in to a dependency problem with your Red Hat because you're trying to pull in some packages from another repository and there are some conflicting (or missing) packages between the state of your system and what the new packages require.
There are a couple of solutions, and I have to admit I'm not a Red Hat user but the first thing I suggest is checking out the EPEL package (see
http://docs.phpmyadmin.net/en/latest/setup.html#red-hat-enterprise-linux). That should be the best and most official way to get going.
If you really wish to use the Remi repository, you'll have to resolve the dependency problems -- which likely means upgrading (or perhaps downgrading) some of the software on your system, which may lead to conflicts with the official repository or even creating circular dependencies on your system. As a result, it's not something I'm comfortable recommending, but there's lots of information online about this sort of thing and a web search for a phrase like "remi rpm_check_debug error glibc santiago" or "dependency problem remi santiago glibc" is likely to find much help.
Finally, as long as you've already got MySQL and PHP installed, you can install your own phpMyAdmin from the official source. Basically you'll download the compressed file and uncompress it to your web root, possibly followed by customizing your config.inc.php. The complete installation instructions cover it in a bit more detail, but that's basically it. Personally, I prefer this method, but you'll have to manually install updates rather than your package manager handling those, so it's not always the ideal solution.
