map from ms_demo don't appear

[root]

hello:

At first one, sorry for my english
I have RedHat 7.1 with Apache and PHP4.0
I download ms_3.3.011.tar.gz and ms_demo.tar.gz, I installed mapserver 
followed the step indicated in MapServer Demo Application Installation 
Instructions.  I commented:

        #MARKERSET symbols/marker.sym
        ...
        #LAYER
        #  NAME roads
        #  MAXSCALE 300000
        #  STATUS ON
        #  DATA ctyrdln3
        #  TYPE ANNOTATION
        #  LABELITEM "road_name"
        #  CLASS
        #    COLOR 255 255 255
        #    SYMBOL 'county_highway_shield' # <= the 'bad' line
        #    LABEL
        #      MINFEATURESIZE 40
        #      MINDISTANCE 150
        #      POSITION CC
        #      SIZE TINY
        #      COLOR 0 0 0
        #    END
        #  END
        #END # county road annotation
the next error was msLoadMap(): Premature End-of-File. Undefined symbol. 
I added END stament befor:
LAYER
  NAME roads
  MAXSCALE 600000
  STATUS ON
  DATA majrdln3
  TYPE LINE
  CLASS
    NAME "Roads"
    COLOR 0 0 0
  END
END # highways
END ######################## My END

The next error was sDrawReferenceMap(): GD library error.  Unable to 
initialize image. Then I commented
#
# Start of reference map
#
#REFERENCE
#  IMAGE graphics/reference.gif
#  EXTENT 393234.393701263 5205405.16440722 495769.579718949 5307959.02579127
#  SIZE 120 120
#  STATUS ON
#  COLOR -1 -1 -1
#  OUTLINECOLOR 255 0 0
#END


After i saw the page but the map image didn't appear

what do you sugest to me about it?

Thank you in advance

Patricio Gigoux