python - How to calculate total number of data cells in raster?

I am using ArcGIS 9.3 and python 2.5. My code is shown at the bottom of this post.

I have a raster containing fire intensity information at 200m cell resolution. I run the script and the first count cell part returns the size of the fire. This works fine.

I then clip the raster using a polygon representing a forested catchment. The new raster represents the area of the catchment that is burnt. When I try to use the same code to count the number of cells of the new raster, it always gives me an answer of zero, even if there is definitely a raster created by the clip tool.

I have tried every combination of every tool I can think of.

my code...

    fire = str(ignitionID) + "_" + str(weatherID) + "_Intensity.asc"
    print "fire: " + fire

    # ---------------------------------------------------------------------------
    # this section calculates the size of the fire for model calibration purposes
    # ---------------------------------------------------------------------------

    # Process: Build Raster Attribute Table...

    the_fire = input_fires + fire
    shutil.copy(the_fire, "C:\\FIRESTORM\\Workspace") # copy the fire to workspace
    the_fire = "C:\\FIRESTORM\\Workspace\\" + fire

    try:
      gp.BuildRasterAttributeTable_management(the_fire, "NONE")
      resultf = gp.GetCount_management(the_fire)  # count num of rows in raster
      countf = int(resultf.GetOutput(0))
      fire_area = countf * 4  # each cell has an area of 4 ha
      print "the fire area = " + str(fire_area) + " ha"


    except:  # the attribute table cannot be created coz the fire is too large

      fire_area = 300000 # default value for large fires 300000 ha
      print "the fire area EXCEEDS 262,140 ha"

    # -----------------------------------------------------------------------------
    # this section calculates the area of the catchments that are burnt by the fire
    # -----------------------------------------------------------------------------


    # Local variables...
    catch_extent = input_catch + "WS_Catchment_region.shp"  # catchment boundary
    fire_raster = "C:\\FIRESTORM\\Workspace\\fire_raster"
    fire_ascii = the_fire
    Output_raster = "C:\\FIRESTORM\\Workspace\\Extract_ASCI1"
    Output_ASCII = "C:\\FIRESTORM\\Workspace\\rastert_extract1.asc"
    catch_burn_area = 0  # reset catchment burn area

    # Process: ASCII to Raster...
    gp.ASCIIToRaster_conversion(fire_ascii, fire_raster, "INTEGER")


    # Process: Define Projection... based on projection of catch_extent
    desc = gp.Describe(catch_extent)
    spatialRef = desc.SpatialReference
    gp.DefineProjection_management(fire_raster, spatialRef)

    # Process: Extract by Mask...
    gp.ExtractByMask_sa(fire_raster, catch_extent, Output_raster)

    # Convert raster to ascii

    gp.RasterToASCII_conversion(Output_raster, Output_ASCII)

    # Process: Build Raster Attribute Table...
    gp.BuildRasterAttributeTable_management(Output_ASCII, "OVERWRITE")

    # count number of rows in raster
    resulti = gp.GetCount_management(Output_ASCII)
    counti = int(resulti.GetOutput(0))
    catch_burn_area = counti * 4  # each cell has an area of 4 ha


    print "catchment area burnt = " + str(catch_burn_area) + " ha"