Are you using conf file?
here is my steps
1- set up conf file - place in AppData\Roaming\qt wallet
rpcuser=1234
rpcpassword=1234
rpcallowip=127.0.0.1
server=1
listen=1
addnode=
rpcport=9077
2- open qt wallet options are in the picture (mappoprusing pnp checked)
3- cmd - C:\Users\Public\Documents\bitblock\sourcecode\miner
4 run - minerd-fx.exe -a bitblock -t 1 --url localhost:9077 -u 1234 -p 1234
then i get the rpc error