I reason with Jena.
I cannot say why, but sometimes resources are referred to without #, like
Resource catRes = infmodel.getResource("http://www.blueobelisk.org/ontologies/chemoinformatics-algorithms/descriptorCategories");
Why not #descriptorCategories? That does not work. But the below requires the dash:
Resource descRes=
infmodel.getResource("http://www.blueobelisk.org/ontologies/chemoinformatics-algorithms/#Descriptor");
I suspect some sort of inconsistency in the OWL file.