Example:

Clojure 1.3.0
user=> (doc clojure.pprint)
ClassNotFoundException clojure.pprint java.net.URLClassLoader$1.run (URLClassLoader.java:366)

It appears it is not safe to call resolve on a symbol representing a namespace; you get the error above. FWIW, I seem to have resolved the problem (see attached diff) by moving the find-ns clause above the resolve clause (in the cond); also the reference to namespace-doc needs to be var-quoted since namespace-doc is private.