I hope this is appropriate for this category - wondering what format the JSON-LD vocab import is expecting. It does NOT like what Schema.org offers on their site.
The error:
expected list of objects as value of ‘@context’ -> ‘rdf’ node, got string
The RDF parser that Omeka uses has a hard time parsing JSON-LD files, possibly because the syntax has so many variants. I’ve found that the Notation3, Turtle, and N-Triples formats are far more reliable to import and easier to compose.