Same problem with Jaunty final, upgraded from Intrepid Ibex. I was able to install it issuing dpkg --force-overwrite -i /var/cache/apt/archives/splashy_0.3.13-3ubuntu1_i386.deb. It won't work either, but after passing the string vga=<number> to the kernel line in menu.lst i was able to see again a splash screen.
Same problem with Jaunty final, upgraded from Intrepid Ibex. I was able to install it issuing dpkg --force-overwrite -i /var/cache/ apt/archives/ splashy_ 0.3.13- 3ubuntu1_ i386.deb. It won't work either, but after passing the string vga=<number> to the kernel line in menu.lst i was able to see again a splash screen.