Avenarius...yes, unfortunately it is possible to fail a personality test. If that were not the case, then it would be difficult to justify its inclusion in the selection process.
I'm afraid you won't find out what sections of the personality test you failed on, if indeed that was the case. If you still want to re-apply next year, use the time wisely.
Shugs, I'd say that currently around 30% of successful candidates get in on their second or third attempt. I find it a real shame when I see candidates applying again but who haven't done anything to improve their chances.