Attempt to properly update...

abilities/FireAura.java

@@ -0,0 +1,28 @@
+import org.bukkit.entity.Player;
+
+import com.garbagemule.MobArena.framework.Arena;
+import com.garbagemule.MobArena.waves.MABoss;
+import com.garbagemule.MobArena.waves.ability.*;
+
+@AbilityInfo(
+    name = "Fire Aura",
+    aliases = {"fireaura","auraoffire"}
+)
+public class FireAura implements Ability
+{
+    /**
+     * How close players must be to be affected by the ability.
+     */
+    private final int RADIUS = 5;
+    
+    /**
+     * How many ticks the players should be on fire for.
+     */
+    private final int TICKS = 20;
+    
+    @Override
+    public void execute(Arena arena, MABoss boss) {
+        for (Player p : AbilityUtils.getNearbyPlayers(arena, boss.getEntity(), RADIUS))
+            p.setFireTicks(TICKS);
+    }
+}