Getting started with PyGTK [Receiving Error]

[Santosh Kumar]

System Information
----------------------------
Ubuntu 11.10
Python 2.7.2

Problem
------------

I think my Ubuntu has PyGTK and GTK both already installed. But
however when I am importing "gtk" in Python interactive mode then I am
getting the following warning:

(.:4126): Gtk-WARNING **: Unable to locate theme engine in
module_path: "pixmap",

(.:4126): Gtk-WARNING **: Unable to locate theme engine in
module_path: "pixmap",

(.:4126): Gtk-WARNING **: Unable to locate theme engine in
module_path: "pixmap",

(.:4126): Gtk-WARNING **: Unable to locate theme engine in
module_path: "pixmap",

On the other side, importing "PyGTK" works well (i.e. I don't receive
any error). What might be error?