Change text

It’s an amazing plugin and as soon as I have finished this urgent customer thing I’ll rate it five stars, because it really helped me out a lot – but where can I change the text that is displayed if one doesn’t fill out a question? The “You did not…”? I can’t find it in any code.
(I know we should do the .mo and .po, and you don’t recommend changing just the code, but could you please tell me anyway?)

And if I click “Show Results” (which I have changed in the German text in the show_exam.php), it displays “Loading” for a short time. Where can I change that to a German version?

Thank you so much for your help and sorry for being unteachable and stubborn about wanting to change the code…

http://wordpress.org/plugins/watu/