changing the color of a progress bar widget

["Norris, Kendall P." <Kendall Norris Honeywell com>]

I am using a progressbar to indicate the number of tests completed.  I want
to change the color of the bar if any test fails and keep it that color i.e.
red.  This will let the operator easily know a failure has occurred, from
across the room.  I already have a color define as a GdkColor and used it to
set the colormap color.  Here is the code, which compiles but crashes when
it tries to execute.

GdkColormap   *fail_colormap;
GdkColor          gdk_color_fail;
GtkWidget        *pbar;

fail_colormap = gtk_widget_get_colormap(pbar);
if(gdk_color_change(fail_colormap, &gdk_color_fail))
    {
    gtk_widget_set_colormap(pbar, fail_colormap);
    }

Thanks, Ken