If you try to log in and get the message that "your account has been marked as inactive," this means that your membership has expired.  

Please click on the "join/renew" button and select "renew" from there (or "join" if you've never been a member).  

Once your membership has been renewed, you will be able to log in again from the main page.  

 Only current members can access the main page login, but everyone can access the appropriate membership form.