Do you see this error keeps repeating or has it gone away after some messages? If you keeps seeing this repeatedly, it means your node went into a fork or being jammed up. Steem network is facing some forking issues ATM. You will have to remove the blockchain subfolder and replace it with the latest copy here - https://mega.nz/#!WEAV0KLZ!McIhGwTEJWcnubo2kuQjrrI5JclYa5cs9q_BaU0f7Sc
blockchain subfolder is located in L:\steem\stm if you follow this guide. Remember to shutdown steemd.exe before replacing the blockchain folder.
Now it works, maybe it was a bad luck block.
Another question:
In the config.ini is correct this settings with N witness for N miners
witness = "1abc"
witness = "2abc"
witness = "3abc"
miner = ["1abc","5key1"]
miner = ["2abc","5key2"]
miner = ["3abc","5key3"]
or this with only 1 witness for N miners?
witness = "1"
miner = ["1abc","5key1"]
miner = ["2abc","5key2"]
miner = ["3abc","5key3"]
Thanks!