I am also hitting this same issue when using Acrobat Reader (9.4.2-Onatty1) on Ubuntu Natty 11.04 64 bit. This was a clean install on 2 different machines. I do have the ia32-libs (20090808ubuntu13) installed on both. All software was added using "Synaptic Package Manager" The following message occurs- (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GdkPixbuf-WARNING **: Error loading XPM image loader: Unable to load image-loading module: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: /usr/lib/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-xpm.so: wrong ELF class: ELFCLASS64 (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): Gtk-WARNING **: /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so: wrong ELF class: ELFCLASS64 (acroread:11504): Gtk-WARNING **: Loading IM context type 'ibus' failed (acroread:11504): Gdk-CRITICAL **: IA__gdk_window_set_icon_list: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_width: assertion `GDK_IS_PIXBUF (pixbuf)' failed (acroread:11504): GdkPixbuf-CRITICAL **: gdk_pixbuf_get_height: assertion `GDK_IS_PIXBUF (pixbuf)' failed