Destroying gnome request dialog from callback

[Spencer Buckner <bucknersa attglobal net>]

I'm using the ImageMagick import command to save an image to a file (a 
png file, for example).  I'm using a gnome request dialog to ask for the 
filename.  In the callback I'd like to destroy the gnome request dialog 
before I issue the import command so that the request dialog doesn't 
have to be moved off the window I'm saving.  I've tried several 
commands: gtk_widget_destroy(dialog), 
gtk_object_destroy(GTK_OBJECT(dialog)), and 
gnome_dialog_close(GNOME_DIALOG(dialog)).  The save succeeds but 
finishes before the request dialog is destroyed so that the dialog 
window is saved on top of the image.  I get the following when using 
gtk_widget_destroy(dialog):

Gtk-WARNING **: invalid class type `gboolean' in cast to `GnomeDialog'

GnomeUI-CRITICAL **: file gnome-dialog.c: line 1101 
(gnome_dialog_close): assertion `GNOME_IS_DIALOG(dialog)' failed.

Is it possible to close the request dialog before the callback finishes?

Thanks.