I think you have clockwork recovery. if so your backup will be in the clockwork/backup folder. the nandroid thats on the root of your sdcard is for sprecovery. the backup there was created by dmupdater. it makes a backup for you when it flashes DM 1.0.
theres a clockwork troubleshooting guide in my sig and that might help. has screen shots to guide you throught it.
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