AnimationEvent has no function name specified

In your Animation editor, you must have clicked the icon for Add Event, looks like a pencil with a small + in the bottom right corner, and is just to the right of the Add Key icon. If you have any Events in your timeline, they are shown at the top as small tall rectangles with an tip at the bottom (pencils I guess?). Anyway, just right click and select "Delete Animation Event".

FYI: these are handy to trigger some code. If you create a script and create a method, I make it a public method but it may not have to be, you can create one of these Events in the timeline of your animation and then assign that method to it. It even has the ability to pass a single parameter to the method if defined with one, so pretty powerful.