Since this plugin isn't updated yet here is a quick fix to update this hook on your own.
Seach for "OnCollectiblePickup" and replace the whole function with the following:

      object OnCollectiblePickup(CollectibleEntity collectible, BasePlayer player)
        {
            var rpgInfo = FindRpgInfo(player);
            if (rpgInfo == null)
                return null;
            int skillPoints;
            if (rpgInfo.Skills.TryGetValue(HRK.Gatherer, out skillPoints))
            {
                foreach (ItemAmount item in collectible.itemList)
                {
                    item.amount = (float)GatherModifierInt(skillPoints, HRK.Gatherer, (int)item.amount);
                }
            }
            ExpGain(rpgInfo, (int)Math.Ceiling(collectible.itemList[0].amount * ExpRateTable[ResourceDispenser.GatherType.Ore] * 2), player);
            Economics?.Call("Deposit", player.UserIDString, collectible.itemList[0].amount * EcoBoost);
            return null;
        }

Its more a quick-fix, not the best way to access the itemList at the fixed index 0 for doing the economic and xp stuff but i didn't care for my case, slight adjustments might be needed if you wanna be more accurate