Check if starting item actually exists before trying to give it to player.

worlds/factorio/data/mod_template/control.lua

@@ -127,6 +127,7 @@ function update_player(index)
     for name, count in pairs(samples) do
         stack.name = name
         stack.count = count
+        if game.item_prototypes[name] then
             if character.can_insert(stack) then
                 sent = character.insert(stack)
             else
@@ -146,6 +147,10 @@ function update_player(index)
             else
                 samples[name] = nil             -- Remove from the list
             end
+        else
+            player.print("Unable to receive " .. count .. "x [item=" .. name .. "] as this item does not exist.")
+			samples[name] = nil
+        end
     end
 
 end