cudaminer.exe -d 0 -H 2 -C 0 -m 1 -l Z12x24 -i 0 -o stratum+tcp://useast.middlecoin.com:3333 -O 1DVgwcCLEhFb2HRGA2PZD3rnNU6w7xNJc7:x
This still doesn't validate on my CPU.
That's weird I'm also on middlecoin. Do you have multiple video cards? Maybe instead of -d 0 try d gtx780
Or if you have only one card, omit it at all. Also, I got best results with the x86 version.