Many semantic web applications require support for mappings between roles (or properties) defined in multiple independently developed ontology modules. Distributed Description Logics (DDL) and Package-based Description Logics (P-DL) offer alternative logical formalisms that support such mappings. We prove that (a) variants of DDL that allow negated roles or cardinality restrictions in bridge rules or inverse bridge rules that connect ALC ontologies are undecidable; (b) a variant of P-DL ALCHIO(