summoning crash

[icedice]

i get this chrash prety often. please help/tell me whats wrong.

error/crash

Exception in thread "Thread-2" java.lang.NullPointerException
at icedice.players.Players.process(player.java:2774)
at icedice.Engine.run(Eingine.java:304)
at java.lang.Thread.run(Thread.java:619)


line 2774 of my player class

NPC np = Engine.npcs[FamiliarID];

the whole method in the player class

if (Engine.players[followPlayer] == null) {
followPlayer = 0;
followingPlayer = false;
}

if (FamiliarID > 0) {
NPC np = Engine.npcs[FamiliarID];
frames.animateInterfaceId(this, 9850, 663, 3);
frames.setNPCId(this, np.npcType, 663, 3);
}
if (skillLvl[2] > 110) {
skillLvl[2] = 110;
frames.setSkillLvl(this, 2);
}

line 304 of my engine class

p.process();

this is not a compiling error. its a cmd/server error. please help