How can I fix this argument in LUA

[Bmw309894]

I am using an old UI but with updated addons and I've only come across one issue and here it is.

Message: ...rface\AddOns\DoomKitty\modules\datatexts\friends.lua:27: bad argument #4 to 'format' (string expected, got nil)
Time: 07/03/16 13:07:17
Count: 10
Stack: [C]: in function `format'
...rface\AddOns\DoomKitty\modules\datatexts\friends.lua:27: in function <...rface\AddOns\DoomKitty\modules\datatexts\friends.lua:10>

Locals: (*temporary) = "%s | %s (%s)"
(*temporary) = "|Kf64|kIronWill|k"
(*temporary) = "IronWill#1602"
(*temporary) = nil
(*temporary) = "string expected, got nil"



Here is the set of strings it is referring to:

local function CreateTooltip()
tool:SetScript("OnEnter", function(this) -------------THIS IS NUMBER 10
GameTooltip:SetOwner(this)
GameTooltip:AddLine("Friends Online")

GameTooltip:AddLine(" ")

for k,v in pairs(friendList) do
local name, lvl, class, area, status, note = v[1], v[2], v[3], v[4], v[5], v[6]
local lineL = string.format("%s %s %s", lvl, name, status or "")
local lineR = string.format("%s", area or "")

GameTooltip:AddDoubleLine(lineL, lineR)
end
GameTooltip:AddLine(" ")

for k,v in pairs(BNetList) do
local BNid, BNname, battleTag, toonname, client, status, broadcast, note = v[1], v[2], v[3], v[4], v[5], v[6], v[7], v[8]
local lineL = string.format("|cffecd672%s|r |cffffffff|| |cffecd672%s|r |cffffffff(%s)|r", BNname, battleTag, toonname) ------THIS IS NUMBER 27
local lineR = string.format("|cffffffff%s%s|r", status or "", client or "")

GameTooltip:AddDoubleLine(lineL, lineR)
end

GameTooltip:Show()
end)
tool:SetScript("OnLeave", function(this) if (GameTooltip:IsShown()) then GameTooltip:Hide() end end)
tool:SetScript("OnMouseDown", function(this, button)
if (not InCombatLockdown()) then
ToggleFriendsFrame(1)
end
end)
end



I do not know how to edit the string properly so that it does not mess up when I mouse over it. Any chance for some help fixing this?