Bob Hope once called Willie Best "one of the best actors I've ever worked with." This can be seen as both a compliment and a play on Willie Best's name.
Bob Hope is said to have enjoyed this role since it was a total change of pace for him. In most of his films he portrays a coward while, in this one, he is heroic.
A joke about Democrats being like zombies has been pointed to for years as evidence of Bob Hope's political affiliations. Most forget that Hope also made a joke about Republicans in El gato y el canario (1939). In fact, Hope made jokes at the expense of both parties throughout his long career, during which he was on good terms with many presidents, Democrat and Republican.
The play, "The Ghost Breaker," by Paul Dickey and Charles W. Goddard, was made twice as a silent film, in 1914 (directed by Cecil B. DeMille), and in 1922. Both silent versions are considered lost. The play was filmed a final time as El castillo maldito (1953), starring Dean Martin and Jerry Lewis. Bob Hope made a cameo appearance in that film.
The castle in the story is called "Castillo Maldito". It means "Castle of the Damned", or "Evil Castle".