I had exactly the same problem and searched around for awhile before figuring it out.
It's not obvious at all
What you have to do is this:
Go to the PlayMaker menu
Open PlayMaker FSM Editor
Dock it (select the top bar and move with mouse until it locks where you want it to)
Then, to get the Actions menu, create a gameobject
Go to Playmaker menu again
Click 'Add FSM to selected'
You will now have an FSM in the Playmaker window (the flowchart)
Bottom right of that window is a button called 'Action Browser', click it.
The Action menu will now appear, dock that and you're done.
If you restart Unity, you're windows will have all the new menus.
Totally not obvious at all, unless I'm missing something?
When you start Unity after installing Playmaker, your first instinct is to change the window tabs, but there is no 'Playmaker' or 'Actions' in the drop down menu. Maybe there should be?
Anyway, hope that fixed your problem.