With Anaconda 11.2.0.62, anaconda traces back while running the %pre scripts due
to a UnicodeEncodeError:

Traceback (most recent call last):
File "/usr/bin/anaconda", line 920, in <module>
    kickstart.processKickstartFile(anaconda, opts.ksfile)
File "/usr/lib/anaconda/kickstart.py", line 834, in processKickstartFile
    runPreScripts(anaconda,ksparser.handler.scripts)
File "/usr/lib/anaconda/kickstart.py", line 960, in runPreScripts
    _("Running pre-install scripts"))
File "/usr/lib/anaconda/text.py", line 461, in waitWindow
    return WaitWindow(self.screen, title, text)
File "/usr/lib/anaconda/text.py", line 93, in __init__
    t= TextboxReflowed(width, text)
File "/usr/lib/python2.5/site-packages/snack.py", line 218, in __init__
    (newtext, width, height) = reflow(text, width, flexDown, flexUp)
File "/usr/lib/python2.5/site-packages/snack.py", line 501, in reflow
    return _snack.reflow(text, width, flexDown, flexUp)
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 2:
ordinal not in range(128)

(note: I retyped this by hand - the line numbers are all right, but there might
be other typos, so double-check if you're grepping for these lines)

I suspect this'll be a problem with any non-english kickstart TUI installs.