Unable to cast object to value in remote events?

I'm trying to create a custom chat GUI, and I am trying to get the event to send several parameters to the RemoteEvent and then be picked up, but when I attempt to do so, it says it is unable to cast value to object? Line 21

local uis = game:GetService("UserInputService")
local typing = false
local isInGroup = false
local assetID = 678387464
local isAlphaTester = false
local notInGroupColor = Color3.new(100/255,100/255,100/255)
local isInGroupColor = Color3.new(255/255,255/255,255/255)
local data = game:GetService("DataStoreService"):GetDataStore("Moderators_CHATTHINGDEV")
local moderator = data:GetAsync(game.Players.LocalPlayer.UserId.."_key",data)

uis.InputBegan:connect(function(input,gameProcessedEvent)
	if input.KeyCode == Enum.KeyCode.Return or input.KeyCode == Enum.KeyCode.KeypadEnter then
		script.Parent.ChatBox.FocusLost:connect(function()
			if script.Parent.ChatBox.Text ~= "" and script.Parent.ChatBox.Text ~= "Click here or press "/" to type!" then
				local message = script.Parent:WaitForChild("ChatBox").Text
				local filteredMessage = game:GetService("Chat"):FilterStringForBroadcast(message,game.Players.LocalPlayer)				
				if game.Players.LocalPlayer:GetRankInGroup(3127454) >= 250 then
					isInGroup = true
				end
				isAlphaTester = game:GetService("MarketplaceService"):PlayerOwnsAsset(game.Players.LocalPlayer,assetID)
			game.Workspace.ChatEvent:FireClient(game.Players.LocalPlayer.Name,isInGroup,isAlphaTester,false,moderator,filteredMessage) --Offending line
	
				script.Parent.ChatBox.Text = 'Click here or press "/" to type!'
			end
		end)
	elseif input.KeyCode == Enum.KeyCode.Slash then
		if not typing then
			script.Parent:WaitForChild("ChatBox"):CaptureFocus()
		end
	end	
end)

script.Parent:WaitForChild("ChatBox").FocusLost:connect(function()
	typing = false
end)

script.Parent:WaitForChild("ChatBox").Focused:connect(function()
	typing = true
end)

game.Workspace.ChatEvent.OnClientEvent:connect(function(player,group,alpha,bot,isModerator,message)	
	local constructedMessage = ""
	wait()
	local position = #script.Parent.Sliding:GetChildren()*20
	local text = Instance.new("TextLabel",script.Parent.Sliding)	
	text.TextColor3 = notInGroupColor
	text.Size = UDim2.new(1,0,0,20)
	if isInGroup then
		text.TextColor3 = isInGroupColor
	end
	text.Position = UDim2.new(0,0,0,position)	
	if not bot then
		constructedMessage = player..": "..message
		if game.Players.LocalPlayer.UserId == game.CreatorId then
			constructedMessage = "[Developer] "..constructedMessage
			text.TextColor3 = Color3.new(1,0,0)
		elseif isModerator then
			constructedMessage = "[MODERATOR] "..constructedMessage
			text.TextColor3 = Color3.new(170/255, 0, 255/255)
		elseif isAlphaTester then
			constructedMessage = "[Alpha] "..constructedMessage
		else
		end
	else
		constructedMessage = "[BOT] "..constructedMessage
		text.TextColor3 = Color3.new(255/255, 170/255, 0/255)
	end
	text.Text = constructedMessage
	text.BackgroundTransparency = 1
	text.TextScaled = true
	text.TextWrapped = true
	text.TextXAlignment = Enum.TextXAlignment.Left
	text.TextYAlignment = Enum.TextYAlignment.Top
	script.Parent.Sliding.CanvasSize = UDim2.new(0,0,0,script.Parent.Sliding.CanvasSize.Y.Offset+20)
	script.Parent.Sliding.CanvasPosition = Vector2.new(0,script.Parent.Sliding.CanvasPosition.Y+20)
end)