What 600 said, is once an object is deactivated, you cannot reactivate from any FSM on the object.
An easy way to accomplish what you want, is to create an empty game object, then associate your moving wall as a child object of the empty game object. When you do it this way, the wall can deactivate itself, but the empty game object (parent) is still active.
For the playmaker code on the Empty Game Object, create a boolean called RESTART and set it to false. Create playmaker Boolean Test action that checks every second for RESTART being true. When RESTART is true, use the set position action, to set its X/Y/Z position in the scene. Then reactivate the action.
Then, when the wall collides with something, have it set FSM BOOL (RESTART), on the Empty Game Object. Then have it deactivate itself.
Or alternative thats even easier... with your current setup. On the final step, dont deactivate the object at all. Instead have it restart at its original position by getting the X/Y/Z values of its original position and storing them in a variable. Then when its time to reset, you just reset its position variables instead of deactivating it.