Aldea Donder: Weird - I thought I'd removed all the references to those particular meshes. Can you post your mod list?
http://img230.imageshack.us/img230/7614/modlist.png
I'm theorizing the cause of the problem may be Clean Redesigned Vivec com/mca patch? It's a shame if it's true, because I'd hate to have to choose between two mods as great as Redesigned Vivec and MCA.
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=8446
Edit: Nope, I've just tried starting a new game with that that mod disabled in my load order, and I still get the same error messages! Although, curiously, they DO seem to pop up quite a bit in the Ebonheart / Vivec area...
Edit: Getting the error in Pelagiad, too... It may be more widespread than I initially thought.