Gdk Gtk warnings and errors from the command line

In the newest version of Ubuntu (11.10) when I run from the command line Gtk complains loudly (over several lines) each time a window is opened. The problem is clearly with the theme - if I change the default from Ambiance to High-Contrast this goes away. Some examples:

travis@hydrogen:~$ emacs foo.txt
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
(emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",

travis@hydrogen:~$ evince test.pdf 
(evince:1566): GLib-GObject-WARNING **: g_object_set_valist: construct property "enable-gestures" for object `EvView' can't be set after construction
(evince:1566): Gdk-CRITICAL **: gdk_window_get_pointer: assertion `GDK_IS_WINDOW (window)' failed
(evince:1566): Gdk-CRITICAL **: gdk_window_get_pointer: assertion `GDK_IS_WINDOW (window)' failed
(evince:1566): Gdk-CRITICAL **: gdk_window_get_pointer: assertion `GDK_IS_WINDOW (window)' failed

I like the themes and I don't want to part with them. How can I fix the command line verbosity from Gtk? I can simply hack the command line to filter out these messages, but I really don't like that idea.

Possibly Related

From a previous version: How to get rid of odd error line...

The Unable to locate theme engine in module_path: "pixmap" messages are a known bug.

To fix it, install the gtk2-engines-pixbuf package

The warnings you get from running Evince are a separate bug. There isn't a fix for that yet as far as I can tell.