3xternal, I did my write up based on the assumption that you were going from having NOTHING installed (no previous attempts) to a full install. It definately sounds like you already have a symbolic link in place that you'll need to get rid of. A symbolic link is simply the Linux equivalent to a shortcut (well, it's more complicated than that, but from a theoretical point of view that's the easiest way to think of it).
You give it a name (in this case "data"), and it targets/points to somewhere else (in this case the "raData" directory on your MMC); then, you can access/read/cd/etc to that target, you can do so simply by refering to the symbolic link. In this scenario, any time RA tries to read from the /usr/share/games/freera/data directory, it will automatically end up reading from /media/mmc1/raData.

A symbolic link is considered a "file" by the file system (even if it targets a directory like the one we're using here), so to remove it you simply need to use the remove file command:
rm /usr/share/games/freera/data

if it gives you an error, just be a bit more "forceful" in telling it that you want to get rid of whatever the heck data is, like this:

rm -rf /usr/share/games/freera/data

That will "force remove recursively" anything that is /usr/share/games/freera/data, whether it be link, directory, file, etc

Once that's done, you can try step 14 again and it should work without problem.