What is the issue?

Loaded only swatter to capture the error while scrolling the in-game addon control panel as follows:

Date: 2014-10-18 07:13:17
ID: 1
Error occured in: Global
Count: 1
Message: ..\SharedXML\AddonList.lua line 575:
   AddOn index must be in the range of 1 to 70
Debug:
   [C]: GetAddOnInfo()
   ..\SharedXML\AddonList.lua:575 AddonTooltip_Update()
   ..\SharedXML\AddonList.lua:452 AddonListScrollFrame_OnVerticalScroll()
   [string "*:OnVerticalScroll"]:1:
      [string "*:OnVerticalScroll"]:1
   [C]: SetVerticalScroll()
   [string "*:OnValueChanged"]:1:
      [string "*:OnValueChanged"]:1
   [C]: SetValue()
   ..\SharedXML\AddonList.lua:448 AddonListScrollFrame_OnVerticalScroll()
   [string "*:OnVerticalScroll"]:1:
      [string "*:OnVerticalScroll"]:1
   [C]: SetVerticalScroll()
   [string "*:OnValueChanged"]:1:
      [string "*:OnValueChanged"]:1
Locals:
(*temporary) = 0

AddOns:
  Swatter, v5.21.5490 (SanctimoniousSwamprat)
  BlizRuntimeLib_enUS v6.0.2.60000 <none>
  (ck=58)