Help me with this error?

The error was in the in game Dev Console so I couldn't copy and paste it, I took a screenshot https://gyazo.com/abef379904022add480adbc87cbe5977 Idk what this error means, help me pls... This is the script that made the error:

function weld()
    local parts,last = {}
    local function scan(parent)
        for _,v in pairs(parent:GetChildren()) do
            if (v:IsA("BasePart")) or (v:IsA("UnionOperation")) then
                if (last) then
                    local w = Instance.new("Weld")
                    w.Name = ("%s_Weld"):format(v.Name)
                    w.Part0,w.Part1 = last,v
                    w.C0 = last.CFrame:inverse()
                    w.C1 = v.CFrame:inverse()
                    w.Parent = last
                    print(""..v.Name.." has been welded in "..script.Parent.Name..".")
                end
                last = v
                table.insert(parts,v)
            end
            scan(v)
        end
    end
    scan(script.Parent)
    for _,v in pairs(parts) do
        v.Anchored = false
    end
end

weld()
script:Remove()