Got the same issue.

I found out there are txs with invalid key_image in the blockchain. The first one is at block 757131.
On May 9th zoidberg commited a security fix from monero (https://getmonero.org/2017/05/17/disclosure-of-a-major-bug-in-cryptonote-based-currencies.html) and now each input is being checked against invalid key_image. That's good.
Unfortunately, by the time he commited the fix there had already been malformed txs in the blockchain. That's why blockchain can't be resyncronized from the beginning now.

I send a pull request to address this issue: https://github.com/cryptozoidberg/boolberry/pull/54