Hi, Trevor, and welcome!
1. The warned symbol is an indication that a poster has broken one of OC.net's posting rules. This typically isn't assigned until the poster has been warned privately and they've broken the same rule again, but it depends on the situation. For more information regarding our posting rules, please click on the Rules tab above or click here
2. Here's a previous thread detailing the star system: http://www.orthodoxchristianity.net/forum/index.php/topic,13447.0.html
Enjoy and thanks for asking!