The issue might not be your formula. If you are using Any Anaplan extension to help with writing the formulas (indentation, color coding, autocomplete) then the exam may reject your formula copy/paste.
Either remove the extension or just use a different browser to take the exam. That's what I did.
Also, @Misbah is right. Remove the word Module from all your module names.
Einas "Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime"