Clojure macros don't work with complex objects

clojure_macros_complex_objects.clj

;; This will work as expected:
(defmacro create-task-with-out [& body]
  (let [[code meta] (get-code-and-meta body)]
    `(let [temp-file-out# (get meta :out-file-obj (create-temp-file))]
       (Task. (future (wrap-with-out temp-file-out# ~@code))
              (assoc ~meta :out-file (.getAbsolutePath temp-file-out#))))))
 
;; Whereas the following snippet won't work:
(defmacro create-task-with-out [& body]
   (let [[code meta] (get-code-and-meta body)
         temp-file-out (get meta :out-file-obj (create-temp-file))]
     `(Task. (future (wrap-with-out ~temp-file-out ~@code))
             (assoc ~meta :out-file (.getAbsolutePath ~temp-file-out)))))
(create-task-with-out (println "hello world") (println "you me too!")) fails with:
;; Giving the exception:
;; Can't embed object in code, maybe print-dup not defined: D:\DOKUME~1\Steffen\LOKALE~1\Temp\clj_1145300297477803280.tmp