There's no spritefont instances placed anywhere in the project, and none of the events specify a character set. So Construct doesn't know what the sprite font character set is. Just drop in an instance to a layout (even an unused layout) and it will work.
To make this easier I've updated Construct revert to defaults in this case, if none are placed in the project. But it means you have to use the default character set.
Also note the events appear to have the same problem as this thread (creating an object in a sub-event, then trying to use it in a sibling event).