Try this:
function rewardTimer(player)
local player = source or player
setTimer ( rewardOnRun, 10000, 1,player )
givePlayerMoney ( player, 3000 )
end
addEventHandler ( "onPlayerSpawn", getRootElement(), rewardTimer )
function rewardOnRun(player)
givePlayerMoney ( player, 3000 )
setTimer ( rewardTimer, 10000, 1,player )
end
You did not give any argument to the rewardOnRun() function.
This would make it work, although i am not sure what you are trying to do with the code.