Related Clues:

• Accident cause, often
• Big mistake
• Trial's companion
• "File not found," for example
• Bug, perhaps
• It may be costly
• Shortstop's blunder
• "File not found," e.g.
• Putting one's foot in one's mouth, e.g.
• Misapprehension
• Bloomer
• 'Does not compute'
• "Oopsy!" evoker
• Ground ball between the legs, for one
• Eraser's target