I couldn't find much of anything to correct the problems, but I can read from the script that some instructions need to be followed:
# To Use
# - You can use this script in one of two ways
# - 1) Set <Bitmap>.sfont to an SFont object then call <Bitmap>.draw_text
# - 2) Call <SFont>.render(<String>) and then blt it to a Bitmap object
# Documentation
# - SFont.new(<String/Bitmap>, <Array>, <Integer/String>)
# - Where the first parameter is a filename (in Graphics/SFonts) or a Bitmap
# object containing the Font data
# - the second parameter is an Array of all of the characters in order in the
# file the default is specified in @@glyphs below you
# - the last parameter is either the width that should be used for the space
# character or the character whose width you want to use for the space
# character the default is " which is the width of the " character if "
# character is not in the glyph then the height of the bitmap will be used
Maybe using it right away will eradicate this strange scripting problem? Also check if it's SDK compliant, though I highly doubt.