how to import an ontology in owl format into virtuoso openlink universal server 7.2 in order to import it into semantic mediawiki
On Windows 10.
As indicated in the support case you logged, assuming the ontology is in RDF form, depending on size you can use one of the Virtuoso insert/load methods to import the ontology into a named graph in Virtuoso. Which includes the Virtuoso RDF Bulk Loader method suggest in the git issue#938 you also logged.
Once loaded the Virtuoso SPARQL endpoint can be connected to by Semantic MediaWiki which has generic support for querying SPARQL endpoints, enabling the owl ontology graph in Virtuoso to be queried by Semantic MediaWiki and made available for use however that is done in Semantic MediaWiki.