[ddd123]

Sorry if i'm doing wrong. This is my first time to post scripting room.
So basically i'm editing and combining Everyone vomit, Showdamage as fortnite and [L4D1/2]Critical Shot
To make sure i can also hear custom sound effect from common infected from shot + random chance to vomit

But when i test i keep getting this annoying spam error and i don't know how to fix it

L 07/30/2021 - 09:19:15: [SM] Exception reported: Client index 0 is invalid
L 07/30/2021 - 09:19:15: [SM] Blaming: l4d_crit.smx
L 07/30/2021 - 09:19:15: [SM] Call stack trace:
L 07/30/2021 - 09:19:15: [SM]   [0] EmitSound
L 07/30/2021 - 09:19:15: [SM]   [1] Line 433, include/sdktools_sound.inc::EmitSoundToClient
L 07/30/2021 - 09:19:15: [SM]   [2] Line 116, plugin.sp::IHurtDamage

I don't see Line 433 since my script total lines are 298
Here's around line 116

public Action:IHurtDamage(Handle:event, const String:name[], bool:dontBroadcast)
{	
	new attacker = GetClientOfUserId(GetEventInt(event, "attacker"));
	new TempChance = GetRandomInt(0, 100);
	int iHitgroup = GetEventInt(event, "hitgroup");
	EmitSoundToClient(attacker, SOUNDER); // emit sound
	if(iHitgroup == 1) // headshot
		EmitSoundToClient(attacker, SOUNDERS); // emit sound LINE 116

	if (TempChance < GetConVarInt(cvarCritChance))
	{
			if (GetClientTeam(attacker) == 2)
			{
				new infected = GetEventInt(event, "entityid");
				decl String:class[20];
				GetEntityNetClass(infected, class, 20);
				new compare;
				compare = strcmp(class, "Witch");
				if(compare == 0)
				{
					return Plugin_Continue;
				}
				else
				{
//					IgniteEntity(infected, 100.0, false);
					damage = GetEventInt(event, "dmg_health");
					damagebonus = damage * damagechance;
					
					VomitEntity(infected);
					EmitSoundToAll (SOUNDS, true);
					
					new Float:x[3];
					new Float:z[3];
					new Float:j[3];
					new String:tName[32];
					new particle = CreateEntityByName("info_particle_system");
					DispatchKeyValue(particle, "effect_name", "boomer_explode_d");
					DispatchSpawn(particle);
					ActivateEntity(particle);
					AcceptEntityInput(particle, "Start");
					Format(tName, sizeof(tName), "part%d", infected);
					DispatchKeyValue(infected, "targetname", tName);
					SetVariantString(tName);
					AcceptEntityInput(particle, "SetParent", particle, particle, 0);
					SetVariantString("eyes");
					AcceptEntityInput(particle, "SetParentAttachment");
					TeleportEntity(particle, x, j, NULL_VECTOR);
					z[2]=z[2]-2;
					CreateTimer(0.1, DeleteParticles, EntIndexToEntRef(particle));
				}
			}
		}
	return Plugin_Continue;
}

Should i also post full sp script file here?
I would greatly happy and appreciate if someone can improve all my noob script and fix it