Here is the message I am getting: 

(21:18:14) | Exception while calling NextTick callback (ArgumentException: An item with the same key has already been added. Key: GunRoll_Sub_Medium)
at System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) [0x000c1] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <eae584ce26bc40229c1b1aa476bfa589>:0
at Oxide.Plugins.FancyDrop.ExportLootSpawn (Oxide.Plugins.FancyDrop+ExportData expData, LootSpawn lootSpawn, System.Int32 level) [0x000c1] in <757786b776b043a4a0168ec11ac4a16b>:0
at Oxide.Plugins.FancyDrop.ExportLootSpawn (Oxide.Plugins.FancyDrop+ExportData expData, LootSpawn lootSpawn, System.Int32 level) [0x000ce] in <757786b776b043a4a0168ec11ac4a16b>:0
at Oxide.Plugins.FancyDrop.SetupLoot () [0x000a7] in <757786b776b043a4a0168ec11ac4a16b>:0
at Oxide.Plugins.FancyDrop.<OnServerInitialized>m__0 () [0x00000] in <757786b776b043a4a0168ec11ac4a16b>:0
at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <c2afd8354b8b4f3ca451cf5a1aa111c3>:0

Here is my config file:

{
"Airdrop": {
"Default radius for location based massdrop": 100,
"Delay between Massdrop plane spawns": 0.66,
"Deploy Smoke on drop as it falls": true,
"Deploy with Audio Alarm on drop": false,
"Deploy with Audio Alarms on drop only during the night": true,
"Deploy with Spinning Siren Light on drop": true,
"Deploy with Spinning Siren Light on drop only during the night": false,
"Disable SupplySignal randomization": false,
"Massdrop default plane amount": 5,
"Multiplier for (plane height * highest point on Map); Default 1.0": 0.25,
"Multiplier for overall flight distance; lower means faster at map": 0.55,
"Prefab effect to use": "assets/bundled/prefabs/fx/survey_explosion.prefab",
"signal rocket explosion timer": 15,
"signal rocket speed": 15,
"Use special effect at reaching ground position": false
},
"Allow Damage Airdrop Settings": {
"Players can shoot down the drop": false,
"Players can shoot down the drop - needed hits": 3,
"Set Angular Drag for drop": 0.0,
"Set Drag for drop (drop resistance)": 0.0,
"Set drop allow to explode on impact": false,
"Set drop chance exploding on impact (x out of 100)": 25,
"Set Mass weight for drop": 0.75
},
"DropSettings": {
"DropDefault": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 25,
"despawnMinutes": 15,
"includeStaticItemList": false,
"includeStaticItemListName": "regular",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 1,
"maxItems": 8,
"minCrates": 1,
"minItems": 8,
"planeSpeed": 475,
"useCustomLootTable": false
},
"DropTypes": {
"custom_event": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 25,
"despawnMinutes": 15,
"fireSignalRocket": false,
"includeStaticItemList": false,
"includeStaticItemListName": "custom_event",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 2,
"maxItems": 8,
"minCrates": 1,
"minItems": 8,
"notificationInfo": "Custom Stuff",
"planeSpeed": 475,
"useCustomLootTable": false
},
"dropdirect": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 50,
"despawnMinutes": 15,
"fireSignalRocket": false,
"includeStaticItemList": false,
"includeStaticItemListName": "dropdirect",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 1,
"maxItems": 8,
"minCrates": 1,
"minItems": 8,
"planeSpeed": 75,
"useCustomLootTable": false
},
"massdrop": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 75,
"despawnMinutes": 45,
"fireSignalRocket": false,
"includeStaticItemList": false,
"includeStaticItemListName": "massdrop",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 5,
"maxItems": 8,
"minCrates": 5,
"minItems": 8,
"planeSpeed": 475,
"useCustomLootTable": false
},
"regular": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 50,
"despawnMinutes": 15,
"fireSignalRocket": false,
"includeStaticItemList": false,
"includeStaticItemListName": "regular",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 1,
"maxItems": 8,
"minCrates": 1,
"minItems": 8,
"planeSpeed": 475,
"useCustomLootTable": false
},
"supplysignal": {
"additionalheight": 0,
"crateAirResistance": 0.0,
"cratesGap": 50,
"despawnMinutes": 15,
"fireSignalRocket": false,
"includeStaticItemList": false,
"includeStaticItemListName": "supplysignal",
"includeStaticItemListOnly": false,
"itemDivider": 2,
"maxCrates": 1,
"maxItems": 8,
"minCrates": 1,
"minItems": 8,
"planeSpeed": 475,
"useCustomLootTable": false
}
}
},
"Generic": {
"Admin messages color": "#c0c0c0",
"AuthLevel needed for console commands": 1,
"Broadcast messages color": "#ffffff",
"Chat/Message prefix": "Air Drop",
"GUI Announce command": "announce",
"Lock DirectDrop to be looted only by target player": true,
"Lock SignalDrop to be looted only by target player": false,
"Prefix color": "#00ffff",
"Prefix format": "<color={0}>{1}</color>: ",
"Show message to admin after command usage": true,
"Time for active smoke of SupplySignal": 210.0,
"Unlock crates only after player stopped looting": false,
"version": "2.9.3"
},
"Notification": {
"Maximum distance in meters to get notified about landed Drop": 500,
"Maximum distance in meters to get notified about looted Drop": 2000,
"Notify a player about incoming Drop to his location": true,
"Notify a player about spawned Drop at his location": true,
"Notify admins per chat about player who has thrown SupplySignal ": false,
"Notify console at Drop by SupplySignal": false,
"Notify console at timed-regular Drop": false,
"Notify console when a Drop is being looted": false,
"Notify console when Drop is landed": false,
"Notify console when Drop is spawned": false,
"Notify console when Drop landed/spawned only at the first": false,
"Notify players at custom/event Drop": true,
"Notify players at custom/event Drop including Coords": false,
"Notify players at custom/event Drop including Grid Area": true,
"Notify players at Drop by SupplySignal": false,
"Notify players at Drop by SupplySignal including Coords ": false,
"Notify players at Drop by SupplySignal including Grid Area": false,
"Notify players at Massdrop": true,
"Notify players at Random/Timed Drop": true,
"Notify players at Random/Timed Drop including Coords": false,
"Notify players at Random/Timed Drop including Grid Area": true,
"Notify players when a Drop is being looted": false,
"Notify players when a Drop is being looted including coords": false,
"Notify players when a Drop is being looted including Grid Area": false,
"Notify players when Drop is landed about distance": true,
"Notify Players who has thrown a SupplySignal": false,
"Notify Players who has thrown a SupplySignal including coords": false,
"Notify Players who has thrown a SupplySignal including Grid Area": false,
"use GUI Announcements for any Drop notification": false
},
"SimpleUI": {
"SimpleUI_Enable": false,
"SimpleUI_FontSize": 25,
"SimpleUI_HideTimer": 10,
"SimpleUI_Left": 0.1,
"SimpleUI_MaxHeight": 0.1,
"SimpleUI_MaxWidth": 0.8,
"SimpleUI_NoticeColor": "1 1 1 0.9",
"SimpleUI_ShadowColor": "0.1 0.1 0.1 0.5",
"SimpleUI_Top": 0.05
},
"StaticItems": {
"DropTypes": {
"custom_event": {
"itemDivider": 2,
"itemList": {
"explosive.timed": 10,
"grenade.f1": 10
}
},
"dropdirect": {
"itemDivider": 2,
"itemList": {
"explosive.timed": 4,
"surveycharge": 10
}
},
"massdrop": {
"itemDivider": 2,
"itemList": {
"explosive.timed": 4,
"grenade.f1": 10
}
},
"regular": {
"itemDivider": 2,
"itemList": {
"cctv.camera": 2,
"targeting.computer": 2
}
},
"supplysignal": {
"itemDivider": 2,
"itemList": {
"explosive.timed": 4,
"metal.refined": 100
}
}
}

Make sure you have the latest version, and if all else fails read the Special Notes.

Adding the info in the Special Note into the data file fixed the issue, ty for your prompt response