Having a quick look at the screenshot, it appears that you have chosen to load the scene based on a variable for the Level Name field.
Is there a specific reason you have for doing so? Have you saved the the Scene filename into that string variable (that is my understanding of how loading scenes by variable works)?
If the answer to the above is 'no' (or 'WTF are you on about?'), then try to uncheck the variable select box next to the 'Level Name' text box. Once you can type into the the text box again, type in; "OnTheMoon" and try to run it- it should work fine.
Basically the 'Level Name' textbox does not need a variable, it just needs you to type in the filename of the scene you are trying to load.
It is my understanding that you could use a string variable instead but for it to work the string variable would need to contain the filename of the scene.
Hope that helps, let us know how it goes.
