Like the title says.
I followed the "Why was your post deleted? See the faq" link which was appended to the deleted answer of mine, trying to find out what I did wrong, but none of the reasons mentioned in the faq seems to match.
What are users supposed to do in such cases?
Edit: I mean generally, not only in my individual case.
I don't know if my individual case is helpful to describe better. Here is what happened:
I think I found an error in a top voted answer of a question. That question dates back to June 2009. The question is not closed, still interesting and has no accepted answer.
The top voted answer was helpful to me, but, at least to my understanding, unfortunately contains an error, too. I just wanted to inform the author about it.
As a complete newbie to stackoverflow (reputation of 1), I am not allowed to add a comment to an answer before reputation 10, so I couldn't use that.
Contacting the author thru his profile (private message or s/t like that) wasn't possible, too. At least I found nothing like it, may be I missed something here.
Flagging the answer felt wrong to me (the author didn't do anything condemnable, quite the contrary, he has helped me. And why bothering a moderator with a correction?).
So I added an answer. Which in turn was deleted then.