Problem displaying tif (works with FWTools)

[Travis Kirstine GIS Tech]

Hi,
I'm trying to display a tif image in mapserver but am encountering a
problem, the tif is visable but is blank (white square).  I created the
images in ArcGis 9.0 as ESRI grids and exported them as tif's.  When I
export the grid and a RGB tif it works fine in mapserver however, if I
export the image just as a tif the image is blank but it works fine if I
load the image in FWTools.  The reason I a basic tif and not a RGB image is
that I'm trying to preserve the elevation data in the raster image

Here is a sample of my mapfile and the tiffs are already georeferanced.  I'm
running mapserver 4.X and have GDAL


This image displays fine
#<<<<<<<<<<<<<<<<<<<---RGB raster----->>>>>>>>>>>>>>>
        LAYER
                NAME tif_rgb
                STATUS ON
                DATA map_app_data/dem_tiffs/test_rgb.tif
                TYPE RASTER
                        METADATA
                                DESCRIPTION "DEM tiff RGB"
                        END
                        MINSCALE 500
                MAXSCALE 100000
                TRANSPARENCY 50
        END

This image displays blank
#<<<<<<<<<<<<<<<<<<<---elevation raster----->>>>>>>>>>>>>>>
        LAYER
                NAME tif_dem
                STATUS ON
                DATA map_app_data/dem_tiffs/test_dem.tif
                TYPE RASTER
                        METADATA
                                DESCRIPTION "DEM tiff"
                        END
                        MINSCALE 500
                MAXSCALE 100000

        END

Thanks for your time
Travis
tkirstine at jdbarnes.com