What's wrong with this mapfile?

[Markus Spring]

Hello list,
I have a problem with the mapfile below:

It doesnt render until I either

* comment out the MAXSCALE in layer MSblock92 
or
* comment out STATUS ON in the legend (resulting in no legend being
created)
or
* activate the fourth class "Nicht bewertet"

If one of these three conditions is met, the mapfile works like a charm.

I do have no explanation for this unlogical behavior and would be very
glad, if someone could point me out what's wrong with this map
definition.

Kind regards - Markus W. Spring

-------------------------------------------------------------------------------------------
# MAPTITLE "Öffentliche Grünflächen und Wald"
#
# Start of map file
#
STATUS     ON
SIZE       500 350
#SYMBOLSET  "/data/web/ms_demo/symbols/symbol.sym"
SHADESET   "/data/web/ms_demo/symbols/shade.sym"
MARKERSET  "/data/web/ms_demo/symbols/marker.sym"
LINESET    "/data/web/ms_demo/symbols/line.sym"
FONTSET    "/data/web/ms_demo/symbols/fonts/fonts.list"
UNITS      METERS
IMAGECOLOR 255 255 255

EXTENT 51199 23918 80829 46732

NAME k1_5_1

#
# Start of web interface definition
#
WEB
  TEMPLATE  /data/web/ms_demo/k1_5_1/k1_5_1.html
  MINSCALE  2000.0 
  MAXSCALE  1550000.0
  IMAGEPATH "/data/web/tmp/"
  IMAGEURL  "/tmp/"
END # WEB

#
# Start of legend
#
LEGEND
  STATUS ON
  LABEL
    TYPE TRUETYPE
    FONT arial
    SIZE 10
  END
END # legend

LAYER
  NAME l24
  DESCRIPTION "Gruenflaechen und Wald"
  DATA /data/ua_shr/flaenutz/shapes/grwald
  TYPE POLYGON
  CLASSITEM "CODE"

  CLASS 
    NAME       "Wald"
    EXPRESSION ([CODE] eq 1.00000000000000)
    COLOR 1 100 0
    OUTLINECOLOR 0 0 0
  END # class

  CLASS 
    NAME       "Parks" # und Grünanlagen, Friedhöfe"
    EXPRESSION ([CODE] eq 2.00000000000000)
    COLOR 1 160 0
    OUTLINECOLOR 0 0 0
  END # class

  CLASS 
    NAME       "Kleingartenanlagen"
    EXPRESSION ([CODE] eq 3.00000000000000)
    COLOR 247 181 103
    OUTLINECOLOR 0 0 0
  END # class

#   CLASS 
#     NAME       "Nicht bewertet"
#     EXPRESSION ([CODE] < 0)
#     COLOR 255 255 255
#     OUTLINECOLOR 0 0 0
#   END # class

END # layer l24

# Background layer blockkarte
LAYER
  NAME MSblock92
  DESCRIPTION "Blockkarte"
  # STATUS DEFAULT
  TYPE Polygon
  DATA /data/ua_shr/muc/shape/block92
  MAXSCALE 50000.0
  CLASSITEM "BLOCK92_"
  CLASS
    NAME "Baubloecke"
    SYMBOL 0
    COLOR -1 -1 -1
    OUTLINECOLOR 165 165 165
  END # class
END # layer MSblock92

END # map