Why wont you register a name for him mabye the image is the thing he cant see. Tell him to try again or at the side of the thing they say if you cant see the image click here to tell the Admin or something like that.
the image thing is a CAPTCHA and sometimes relies on cookies
Tell him/her to re-enter the confirmation code . The confirmation code he typed were wrong . Look carefully for Big or Small letter .
The password sent in confirmation can be a combination of leters, numbers and special caracters.
Something like klGh_9HH
Notice the use of upper and lower case leters.
Make sure to type it EXACTLY as given.