I just wanted to add to this, for anyone who may be having the same issue and ending up here. I've been doing some testing and exploring the "playerprefsx" actions a little more thoroughly after Jean figured out what the issue was.
For your playerprefs to work properly, it's necessary that each new key is entirely unique.
Each key has a title. In the PlayMaker variables window, when your key is selected, this is the "Edit Variable" field. This is what prefs-related FMS will use to access the key. If you have multiple keys, they must have different names in the Edit Variable field.
In addition to the name of the key, the key has its own String (essentially a value). In the PlayMaker variables window, when your key is selected, this field is titled "string" and is directly below the "Edit Variable" field. The String component of the key must also be unique from all the other "string" components on other keys! To make this simple, I just set both the "edit variable" and the "string" to the same thing within one key.
Like so:
First Key: Edit variable = dinosaurkey
String = dinosaurkey
Second Key: Edit variable = happykey
String = happykey
Notice how the variable and string fields may match inside of their own key, but do not conflict with the same fields inside other keys.
The following will also work:
First Key: Edit variable = dinosaurkey
String = blahblahblah
Second Key: Edit variable = happykey
String = horray
Even if your FSMs end up assigning a new value to the key to store data(as mine do), it's essential that you still have both of these fields filled out with a unique value in the variables (or global variables) window. This way when your game starts, your keys have a "value", even if it does get overwritten. Unity will throw a fit if you ask it to overwrite an empty key, or a key that isn't 100% unique.
As a final note, typing a "0" into either the Edit Variable or String fields when editing a key will also make Unity unhappy.
