Just to verify: On the Home > Applet Settings > GPE Summary, do you have "Show Todos" checked? You should see a "(no todos)" label at the bottom of the summary box. If you don't see it most likely you don't have the todos enabled.

I also recall you needed to enter something on the calendar first to create the actual Todo Database. I've used GPE Summary since day one of my tablet and have never had any problem with it. It is maybe the single most important app I use, strangely. It almost gives my the same performance I had PIM-wise with my Tungsten E2.

Not much to do about the military time setting, unfortunately.