center map on x,y coordinates

[Elisabeth Nolz]

hi list.

i posted this problem months ago, and altough i got lots of answers (thanx to
all) i couldn't solve it. but now i need this function again and have to get
it working as soon as possible.

i want to center my map on x,y coordinates. this is the link i use:
http://localhost/cgi-bin/mapserv?map=map.map&mode=map&mapxy=339989.20+1646.20&scale=20000

i can see the background-color of the map, but nothing else. here's an
abstract of my mapfile:
NAME TEST
STATUS ON
SIZE 400 300
EXTENT 1150 340000 1900 339550
UNITS meters
SHAPEPATH "data"
IMAGECOLOR 230 230 230
IMAGETYPE GIF

LAYER
  NAME "strasse"
  GROUP "Eintausend"
  METADATA
    LYRNAME  "Strasse"
  END
  MINSCALE 500
  MAXSCALE 1000
  DATA "vektor/strasse"
  STATUS ON
  TYPE POLYGON
  CLASSITEM "ID"
  CLASS
    NAME "Strasse"
    EXPRESSION /./
    OUTLINECOLOR 0 0 0
#    COLOR 0 0 0
  END
END

please, can someone figure out whats going wrong?
thx,
elisabeth.