If I use the file from https://github.com/mumez/PunQLite/tree/master/binary/mac at least the library is found. The db file is not created though resulting in a PqCursorError in keys
db := PqDatabase open: 'test.db'. db at: 'Smalltalk' put: 'COOL'. db at: 'Pharo' put: 'HOT'. db at: 'Smalltalk' ifPresent: [:data | data asString inspect ]. Transcript cr; show: db keys.