This error occurs if the drone launches while empty. It seems to try to read from a table of its contents but it crashes out when it doesn't get anything back.
Recommend either preventing the launch entirely (removing a timeout if present), or drone crashes shortly after launch with notification.

Error while running event Long_Range_Delivery_Drones::on_tick (ID 0)
...e_Delivery_Drones__/script/long-range-delivery-drone.lua:331: bad argument #1 of 2 to 'next' (table expected, got nil)
stack traceback:
[C]: in function 'next'
...e_Delivery_Drones__/script/long-range-delivery-drone.lua:331: in function 'deliver_to_target'
...e_Delivery_Drones__/script/long-range-delivery-drone.lua:494: in function 'update'
...e_Delivery_Drones__/script/long-range-delivery-drone.lua:1256: in function 'update_drones'
...e_Delivery_Drones__/script/long-range-delivery-drone.lua:1300: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>

As an option, part of the deliver_to_target function could be wrapped in a try/catch block — in that case, empty planes will still arrive and get destroyed, but at least it won’t crash anymore.

  local success, err = pcall(function()
    local name, quality_count = next(source_scheduled)
    local quality, count = next(quality_count)
    if name and quality and count then
      count = math.min(count, get_stack_size(name))
      local target_scheduled = self.delivery_target.scheduled
      local removed = self.inventory.remove({name = name, quality = quality, count = count})
      if removed > 0 then
        self.delivery_target.inventory.insert({name = name, quality = quality, count = removed})
      end

      source_scheduled[name][quality] = source_scheduled[name][quality] - count
      if source_scheduled[name][quality] <= 0 then
        source_scheduled[name][quality] = nil
      end
      if not next(source_scheduled[name]) then
        source_scheduled[name] = nil
      end

      if target_scheduled[name] and target_scheduled[name][quality] then
        target_scheduled[name][quality] = target_scheduled[name][quality] - count
        if target_scheduled[name][quality] <= 0 then
          target_scheduled[name][quality] = nil
        end
        if not next(target_scheduled[name]) then
          target_scheduled[name] = nil
        end
      end

      delivery_time = self:make_delivery_particle(name)
    end
  end)

The game also crashes if you send a drone using a drone — because it tries to add a number to a table. A quick fix would be to add a type check for a number.

function safe_number(value)
  return type(value) == "number" and value or 0
end

and use it in update_logistic_filters

self.logistic_section.set_slot(slot_index, {value = DRONE_NAME, min = 1 + safe_number(self.scheduled[DRONE_NAME] or 0)})

I have the same error

我在Long Range Reusable Delivery Drones
by sanovskiy
这个模组里遇到了同样的错误，按这个方法修改后暂时没什么问题。唯一的缺点就是，请求站仍然会在错误的站点发送请求。以前游戏进行到这里就崩溃了，现在会等待半天，然后才会从正确的站点发送材料过来。

可能最好的方案是在没有机器人指令平台的地方使用它。如果在有机器人指令平台的地方，不要往仓库预先填充物品。

经过测试后，我有以下猜想：
请求站有请求时，模组会扫描哪些站点符合要求，如果没有符合要求的站点，则不建立请求，但是假如一个站点在机器人指令平台的物流系统里，而这个系统里有足够的材料，那么它就会把请求建立在这个站点，正常情况时游戏本身的物流机器人会把物资运到站点，满足数量请求后远程无人机就会运送。但是有一种情况是不正常的，就是这个站点已经充满了其他种类的物资，没有多余的格子放请求的物资，但是mod仍旧会把请求建立在这个站点，可能它认为物流机器人会把物资运过来，但事实上因为没有足够格子，物流机器人永远不可能把物资运送过来。
模组设计上应该有个最大的等待时间（或许这个时间是等待机器人把物资运过来，幸好不是等到天荒地老），时间一到，就算物资不够，也会运走（我自己测试差不多在2分钟），原来的模组里到这里飞机会运送空包出去，接着模组会崩溃，但是在以上解决办法里（感谢kolhov
），游戏不会崩溃，但是请求不能满足，它仍会在这个地方重新建立请求。如此进入循环。
改进建议：在某个仓库建立请求之前，增加一个检查，看是否有足够的格子能满足请求物资装填进来。如果能再增加一个GUI功能，查看哪些请求站的请求未能得到满足，那就更好了。

@kolhov
大神，能否看一下另外一个模组Long Range Reusable Delivery Drones （by sanovskiy），它的无人机在返回仓库时如果恰好手动拆除了这个仓库，那么游戏必然崩溃，我不是很懂代码，尝试修改了一下，不能达到效果。如果您有时间的话，能否研究出解决方案？
作者不知道是太忙还是已经放弃该模组，我的反馈得不到回应。

我已经研究出来了

@kolhov
大神，能否看一下另外一个模组Long Range Reusable Delivery Drones （by sanovskiy），它的无人机在返回仓库时如果恰好手动拆除了这个仓库，那么游戏必然崩溃，我不是很懂代码，尝试修改了一下，不能达到效果。如果您有时间的话，能否研究出解决方案？
作者不知道是太忙还是已经放弃该模组，我的反馈得不到回应。

this is a fork from this mod, so if you insert the code that is above it should work, I don't have time to do it myself right now.