Making a maintenance script to run in automator

I have a mac mini and it is off durring the night so the maintenance scripts don't run. I have been using onyx and sometimes terminal to run the scrips. But after upgrading to SL I saw that automator has an ical alarm trigger and I wanted to make a workflow that runs the maintenance scripts that is triggered my my cal. I have no idea how to do this, I tried using the run shell and scrip actions but it gives me a sentax error. Does anyone know how to do this?

Thanks,
Geoff