I HAVE DOWNLOADED THE JBOSS FORUMS AND I DON'T KNOW HOW TO INSTALL IT. THERE IS A FOLDER CALLED "PORTAL-FORUMS.EAR" THAT HAS INSIDE IT THREE FOLDERS AND A .JAR FILE. THE FOLDERS ARE NAMED "PORTAL-FORUM.WAR" , "PORTAL-FORUM-SAR" AND THE .JAR FILE IS NAMED "portal-forums-lib.jar".
The forums download page (http://labs.jboss.com/portal/jbossforums/downloads) has a link to the documentation, which provides installation instructions. Did you read that?