I have a custom splashy screen set up on Debian Lenny, following this guide:
http://splashy.alioth.debian.org/wiki/faq
My entry is the default "splash vga=791 quiet", not 792 though - not sure if that is different for you?
Have you tried the splashy image while running, just to make sure it works ok? Run "sudo splashy test" and see if you get the screen to load properly. If not, check your installed themes, and try installing a different one and test.