Thank you for trying Ministg. Check out the Documentation.
Install with cabal install from the root directory. Or cabal install ministg from anywhere to install from hackage.
Bernie Pope: http://www.berniepope.id.au, alternatively issues on github.
cd test
ministg sum.stg
Note that unless the flag --noprelude is passed, it'll expect it.
That's why you have to explicitly cd into the test folder.