Run rake using Automator

I have install ruby using RVM. Next I create workflow in Automator, which detects new files in folder and then copies them to another dir. The next thing I want - to switch to those folder and run few rake scripts. I have tried to add next step to workflow: cd ~/blog/octopress/ rake generate rake deploy But it's failed with error: > Run shell script failed - 1 error. Rake aborted What I'm doing wrong?