FYI, if it is a MultiBit HD wallet and you have your seed... and you have an Android or iPhone, you can install BreadWallet and restore your wallet there to access your funds until the MultiBit devs release an update to fix this issue.
If you don't have your seed, but you have your wallet and wallet password... you can use
decrypt_bitcoinj_seed.pyw by gurnec to recover your seed, then restore to BreadWallet...
Finally, if you have a MultiBit Classic wallet and know your wallet password (or you have a MultiBit HD wallet, know your password and can't use BreadWallet)...
I have written some python scripts based on gurnec's, that will allow you to extract your private keys either from a MultiBit HD "wallet file", a MB Classic "Key Backup" file or a MB Classic "wallet file"...