HiroS, you need to update your difficulty adjustment algorithm to the Darkcoin fixed KGW algo. There are a lot of exploits that can be performed on KGW that cannot be on the Darkcoin fork.
Thanks for the info. I am looking at it now, from what I read the exploit is down to people messing with the block time to play with KGW. Hirocoin limits the acceptable block time greatly but need to check how little time manipulation is required for them to effect KGW negatively. If you have more info or links let me know.
FYI, pool bounty has been paid to
http://benchcryptopools.myvnc.com/hirocoin/