Argument line 7: StrikeBall not a valid member of backpack Also, this giver is to give a player that does not already have an the item and is on the same team as the color of the block.
local Giver = script.Parent
local Gear = game.ServerStorage.StrikeBall
local debounce = false
local function FindTool(player, tool)
local Character = player.Character
local HoldingTool = Character:FindFirstChild(tool)
local BackpackTool = player.Backpack:FindFirstChild(tool)
if HoldingTool ~= nil or BackpackTool ~= nil then
return true
end
end
Giver.Touched:connect(function(part)
local Player = game.Players:GetPlayerFromCharacter(part.Parent)
if Player ~= nil and Player.TeamColor == Giver.BrickColor and debounce == false and Player:FindTool("StrikeBall") == nil then
debounce = true
Gear:Clone().Parent = Player.Backpack
end
wait(5)
debounce = false
end)

2 comments
The main error I can see is on line 18; You only gave 'FindTool' one Argument, and not the required two Arguments!
Change 'Player:FindTool("StrikeBall")' to 'FindTool(Player,"StrikeBall")'