Couple things to check:
1. Open RCM's failure list view and double click on a failure code to open failure form. Verify that action tab has an action code defined.
2. Close work order edit form, close work order form (by work order form I mean the form with multiple tabs).
3. Open work order list form, double click to open the work order form.
Click edit button, now click on the lookup button to select action. You should see the action code displayed in step 1.
The action lookup form is missing a refresh button at this time and will be added at the upcoming release which is around the end of August.