While 50p has their eyes examined,
I'll point out your mistake, and it's an easy one
You can trigger client events to only trigger on specific clients - which is what you want in this case. In your Server file you have:
function deathHandler( playerSource )
local zufalldeath = math.random(1, 4)
local zufallskin = math.random(7, 288)
triggerClientEvent ( "onGreeting", getRootElement())
...
and you can modify that triggerClientEvent call to only trigger for the one player you want - in your case, "playerSource". here's the triggerClientEvent syntax so you can see what we're dealing with:
bool triggerClientEvent ( [element triggerFor=getRootElement()], string name, element theElement, [arguments...] )
https://wiki.multitheftauto.com/index.ph ... lientEvent
so you modify your triggerClientEvent to:
triggerClientEvent ( playerSource,"onGreeting", getRootElement()) --who to trigger for, what event to trigger, who triggered it