\\solved

[quality]

\\

function stopDamage () 
    if getPlayerTeam(source) == getTeamFromName("Admin") then 
      cancelEvent() 
    end 
  end 
addEventHandler("onClientPlayerDamage", getRootElement(), stopDamage) 

had to specifiy type="slient" in meta.xml

[Walid]

Try this

addEventHandler("onClientPlayerDamage", localPlayer, 
function(attacker) 
    if (attacker and getElementType(attacker) == "player" and attacker ~= source) then 
        if ( getTeamName( getPlayerTeam( source ) ) == "Admin" ) then  
            cancelEvent() 
        end 
    end  
end  
)