Thread: Null Pointer Exception in Emulous

Code:

Exception in thread "main" java.lang.NullPointerException
        at server.npcs.NPCHandler.process(NPCHandler.java:459)
        at server.Server.main(Server.java:23)

Base: Emulous

That is my error. It all pointed the the process in NPCHandler.java. Now this only happens after about 45 mins. I added some code to it for slayer. So here is the part of my process in NPCHandler that gives me the error

Code:

				if (npcs[i].isDead == true) {
					if (npcs[i].actionTimer == 0 && npcs[i].applyDead == false && npcs[i].needRespawn == false) {
						npcs[i].updateRequired = true;
						npcs[i].facePlayer(0);
						npcs[i].killedBy = getNpcKillerId(i);
						npcs[i].animNumber = getDeadEmote(i); // dead emote
						npcs[i].animUpdateRequired = true;
						npcs[i].freezeTimer = 0;
						npcs[i].applyDead = true;
						npcs[i].actionTimer = 4; // delete time
					} else if (npcs[i].actionTimer == 0 && npcs[i].applyDead == true &&  npcs[i].needRespawn == false) {
						int p = npcs[i].killerId;
						Client c = (Client) Server.playerHandler.players[p];
						npcs[i].needRespawn = true;
						npcs[i].actionTimer = getRespawnTime(i); // respawn time
						dropItems(i); // npc drops items!
						npcs[i].absX = npcs[i].makeX;
						npcs[i].absY = npcs[i].makeY;				
						npcs[i].HP = npcs[i].MaxHP;
						npcs[i].animNumber = 0x328;
						npcs[i].updateRequired = true;
						npcs[i].animUpdateRequired = true;
						if (npcs[i].npcType == 1653) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1616) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1637) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1619) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1624) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1610) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1613) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 1615) {
							c.getPA().addSkillXP(2000, 18);
						}
						if (npcs[i].npcType == 2783) {
							c.getPA().addSkillXP(2000, 18);
						}
							c.getPA().refreshSkill(18);
							c.getPA().requestUpdates();
					} else if (npcs[i].actionTimer == 0 && npcs[i].needRespawn == true) {
					
						int old1 = npcs[i].npcType;
						if (old1 == 1267 ||old1 == 1265) {
							old1 += 1;
						}
						int old2 = npcs[i].makeX;
						int old3 = npcs[i].makeY;
						int old4 = npcs[i].heightLevel;
						int old5 = npcs[i].walkingType;
						int old6 = npcs[i].MaxHP;
						int old7 = npcs[i].maxHit;
						int old8 = npcs[i].attack;	
						int old9 = npcs[i].defence;
						
						npcs[i] = null;
						newNPC(old1, old2, old3, old4, old5, old6, old7, old8, old9);

					}

				}

I always get the errors around the part where I have it give slayer xp. Now I am not sure why this works for awhile then aroun the 45 min mark I get the above error. Any ideas?