Your first few posts are moderated and must be approved before they will appear. This is for spam purposes. Since mods are volunteers, we sometimes approve the posts right away and sometimes it takes awhile. Occasionally they get lost in the queue.
Classifieds are the same way. The classifieds are for the members of the community, not just anyone who wants to sell stuff but not contribute to the community. This change was made because while mp3car is not responsible for scams, they were occurring in the classifieds and mp3car was asked for help in resolving the issue. Investigating the complaints often results in "he-said, she-said" accusations and it was sometimes not clear what the right resolution is.
I can check the email situation, but generally the email access is user-set. If a user selects that he/she is willing to accept email from members of the forum, it will go through. If it is not set, you cannot send it. You may try emailing me and see if it works as mine is turned on.
I'll check the 5 message limit. I think it should be 100.