I'm trying to mine the first block of a Scrypt coin I just created for fun, but whenever I use the command

setgenerate true -1
it returns:
Method not found (code -32601)
Tried on 2 diffrent machines. Same results.
So then I tried this method, its from walletbuilders:
Download the latest version of cpuminer from here and extract the zip file.
Create a .bat file named mine.bat and paste the following text into mine.bat.
minerd --url=http://127.0.0.1:4210 --userpass=rpc_user:2922b8f943594597572c47bba
Save the file inside the extracted cpuminer folder.
Open your wallet and execute mine.bat to start mining your first coins.
Im running this for 20 minutes or so now, and the only result is: accepted 0/11 booooooooooooo
What am I doing wrong?