It looks like multibit classic wallets can get (easily?) corrupted. You should ask the creator of Multibit to help you. I managed to find out that between 2 different versions of wallets the data between offsets 0x3a and 0xae is unchanged, so your private key may be there. Of course, I have no idea how to decrypt it.
Thank you , i was thinking about contacting multibit , but there no official contact info , i hope someone knows how to decrypt private key , for now it's seems only option.