remote desktop 3.6 with 3.5.3 clients

I have a mac lab of 30 iMacs running Snow Leopard 10.6.8. My Admin computer is running Mountain Lion 10.8.2. I can't seem to run any Automator actions like setting my desktop picture as the desktop pictures of my Lab. I was able to do this before my upgrade to Mountain Lion. Is there any way to make this work? I rely on automator a lot for work and would be seriously sad if I have to go back to the manual way of doing things (or use another computer for ARD).