Ok, we're half way through. The kernel boots, but the rootfs has issues. The rootfs for the OpenDingux kernel needs to be named "rootfs.bin", but for legacy dingux it was "rootfs". That's probably why qbert's tutorial has it that way.
Now I see 3 possible issues:
1) the card or the rootfs file is corrupted/damaged (check the md5sum for the rootfs, it should be ff1fc5ba65f759c0723bb8433e142809 for opendingux-rootfs.2012-06-16.bin)
2) You try to use OpenDingux rootfs with legacy kernel
3) Windows tries to hide the extensions and you renamed the file as "rootfs.bin.bin"