Attempting to run the README contract interactions with curl results in 'Private Key not available'

[Ferret-san]

Environment:

Windows 10 machine with WSL2 (Windows Subsystem Linux) running Ubuntu 20.04 LTS

What was run:

curl --header 'Content-Type: application/json' --data '{"id":"10","jsonrpc":"2.0","method":"eth_sendTransaction","params":[{"from":"0xcb3cb8375fe457a11f041f9ff55373e1a5a78d19","gas":"0x6691b7","gasPrice":"0x174876e800","data":"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"}]}' http://localhost:23889

Wanted:

{
  "jsonrpc": "2.0",
  "result": "0x6da39dc909debf70a536bbc108e2218fd7bce23305ddc00284075df5dfccc21b",
  "id": "10"
}

Got:

{"jsonrpc":"2.0", "error":{"code": 100, "message": "qtum [code: -4] Private key not available"}, "id":"10"}

[Ferret-san]

Need to update README as the account used for in the examples is not part of the set of default accounts.