can't do factory reset or start the tablet

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http://forum.xda-developers.com – Hello, I've got a problem and I'd be very happy for any advice. I am on rom JellyBean AOSP. I was using my Transformer and sound stopped working. So I decided to turn it off and on again and when I tried to turn it on and I wasn't able to start tablet anymore. I'm stuck on the first screen you see when you turn on the tablet. So I wanted to do factory reset in the recovery. In recovery everything works allright. When I click on the factory reset it says error when deleting something in /data/ and I also can't do "Format /data/" because of the same error. Here is the log from (HowTos)