New members can't use the PM function until they have 20 posts. This is to avoid abuse of the PM function by drive by spammers who sign up to the forums just to spam. Other areas of the advanced Profile settings will also be barred, that might be what you are experiencing.
Well ... that explains it. Thank you!
I guess it doesn't matter that I registered in 2006 and haven't spammed anyone yet.
I did try the "Help" file, but it didn't provide the detail you have provided. However, it did reference the possibility of customization altering the expected behavior of the forum software. I looked for a FAQ file to explain any customizations or common concerns that new forum members would have, and didn't find one.
The other issue I had been seeking an explanation for was why I could see the email icon (and my email address) even though I had "Hide email address from public" checked. I was very uneasy about having used the forum until I had a friend register and login and confirm for me that my email address was not visible to others. It's a leap of faith to assume that others can't see it ... without that confirmation.