No such var: tv/set-property! error

[wmfairuz]

Hi,
I'm trying out the example at http://titanium.clojurewerkz.org/articles/transactions.html specifically this code:

(tg/transact! (tv/set-property! (tv/refresh stale-node) :name "Zack")) ;; Should work!

But I got this error: clojure.lang.Compiler$CompilerException: java.lang.RuntimeException: No such var: tv/set-property!, compiling:(/home/vagrant/sandbox6/src/sandbox6/core.clj:52:1)

p/s: I'm using the live mode of LightTable