FB question: Why can't my friends post on my wall, if "friends can post on my wall" is checked "enable?"?

Someone told me she can’t post on my wall. I went to Privacy settings and see that “friends can post on my wall” is checked “enable.” Am I missing something here? I just asked another friend to try posting something, and she did not, and she had to go, so I can’t ask her but the fact that she did not post leads me to believe that she could not.

Am I missing something here?