I've had the same problem. I've tried to use it for the first these last few days. I am using an SD1100 IS with firmware version 1.01a.
1. I formatted my 2GB sd card in the camera, so I know it's formatted correctly.
2. Using gparted in Ubuntu, I made sure the "boot" flag was selected for the sd card, so it's bootable.
3. DISCBOOT.BIN is in the root directory of the card.
4. I locked the card and put it in my camera.
5. I turned my camera on
Bug: Displays "Card is Locked" whether in play or record mode. Pressing print button does not open Alt mode.
I don't know what else is to be done.