Problems with namespaces in KnowRob

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I'm trying to follow the tutorial on reasoning about actions on the KnowRob website.

As suggested in the tutorial, I execute

$ roscd knowrob_basics_tutorial
$ rosrun rosprolog rosprolog knowrob_basics_tutorial
?- owl_parse('owl/pancake-making.owl', false, false, true).

and get a very hopeful

true.

I then proceed with

?- class_properties(pancake:'MakingPancakes', knowrob:subAction, Sub).

that unfortunately answers with

ERROR: namespace `pancake' does not exist
^  Exception: (11) setup_call_catcher_cleanup('$expand':'$set_source_module'(user, user), '$expand':expand_goal(class_properties(pancake:'MakingPancakes', knowrob:subAction, _G239), _G303, user, [user, system]), _G373, '$expand':'$set_source_module'(_G328, user)) ?

The namespace is correctly included in the OWl file

<rdf:RDF
    xmlns         ="&pancake;"
    xmlns:pancake ="&pancake;"
    xml:base      ="&pancake;"
    xmlns:knowrob ="&knowrob;"
    [...] >

so it's really hard for me to understand what's going on. How do I ensure the pancake namespace is correctly included? Is there a way for me to print out all the namespaces?