As mentioned, this is a dependency issue which may be better suited to the AskUbuntu Stack Exchange website or Unix and Linux Stack Exchange website.
libgdk-pixbuf2 is quite old, and is part of GTK1, which has been discontinued for quite some time. It looks like this was resurrected from an old stable release a few years back, and there has been an experimental package imported into Maverick and Natty (Ubuntu releases) but should be available in the Debian repositories as well.
If you do the following you may find the new package using APT;
sudo aptitude update
sudo aptitude show gdk-pixbuf
sudo aptitude install gdk-pixbuf
If you get a GPG error (signatures couldn't be verified because the public key is not available) then try to get the key as well;
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com