prof of work too weak not correct

[dinastyoffreedom]

After update last version the blockchain start to write many proof of work too weak also for previous correct blocks, and cannot sync
I comments out the code to can work correctly
I also found some other issue always concerning the blockchain syncronization trying to open wallets with simplewallet some time generate a a segmentation fault and after that wallet result corrupted.
and these problems do not allow to wallet gui to work properly.