When one chooses Russian language to install, installer makes
default locale to be russian. This means that most system utilites
trying to output russian text. But init scripts not told to
load russian fonts and switch console codepage to user-loadable fonts.
So all these messages looks completely unreadable.
Also it does not install cyrillic fonts for unknown reason,
so all messages in X on buttons, or any othe places is also unreadable.
This bug is fixed in the next release of Red Hat Linux.