A couple preliminary things here about the error, besides the inevitable Ace2 is dead.
That error in the parent post fires 100% of the time if you have (the last r1101) Ace2 loading disembedded in WoW 4.0.1 live. Still researching to find out what mod--if anything--the error is connected to. Or if its just a plain bugout in AceComm-2.0.
AtlasLoot Enhanced itself does not use Ace2 much, its pretty much Ace3. With the annoying exception of Dewdrop, which requires AceLibrary (from Ace2). Even so, it does not use AceComm-2.0.
Its AtlasLootFu module uses more Ace2 libraries than Dewdrop does, however. But still no AceComm-2.0. And you don't need that module active, AtlasLoot also includes a built-in LDB feed.
It doesn't matter how easy a fix would be. We're not going to fix it.
We want Ace2 to die. If we start fixing it now, authors will never move on, and we'll be stuck in a endless spiral of hacks and fixes.
We've given everyone a fairly early notice that Ace2 is at its end, and people should move on.