Yes, I've encountered that "cant find animation state / attack 1" message myself, but it wasn't confined to models using the main class meshes/skeletons. I really have no idea what's going on with that - sorry I can't offer much help
I've run into it before, in a situation similar to Asmodeo - using a monster as a town NPC.
In CPHB, you might be aware that Krissie will be turned into all kinds of other forms regularly as apparently La Rive has no qualms about experimenting on her pet.
(Actually way before that I was toying around with the idea of Revail rarely spawning as a neutral NPC on dungeon floors, kind of like the travelling merchant, suggesting that she, too, was adventuring and exploring the dungeon, just like the player. It would probably have run into similar problems)
Whenever Krissie was able to turn into an Ember Mycon or Blade Mistress (and I think interestingly enough a Dark Priestess as well), the game would crash in town.
Now, both of those monsters use .animation files that have been tinkered with. The Ember Mycon to give the pet modified ambient particles that suit its colouration, the Blade Mistres to add the lslash and rslash2 animations.
I never really solved that, I essentially created a workaround. I chose to simply not have Krissie turn into an Ember Mycon at all. For the Mistress and Priestess, I instead had it use Valeria's model, as there seems to be no issue with that appearing in town
I did have to adjust the skins a little (you may remember a video concerning that in the CPHB thread), because there are some mild differences between the base Zealot and Valeria. For example, the Zealot wears a headdress, while Valeria does not, and part of the base of the headdress is on the Zealot's forehead when you look at the skin. So I head to remove that, otherwise there would be this random triangle on their foreheads, without the rest of the headdress attached to it.
So to me it looks like there's an issue using monsters that have been modified in certain ways as town NPCs.
I've tried on some occasions to summon all the suspected offending monsters in town right after clearing the mod cache. Interestingly enough, it wasn't always the same monster that would crash the game, and sometimes it wouldn't crash at all (at which point I would exit, clear cache, reload, and try again), so in my current situation it seems kind of inconsistent >_>Torchlight dropping animations is common enough to be an issue (though oddly never when you're running it through TorchED) but not enough that anyone's found the actual cause for it.
Come to think of it, I've indeed never had it happen in TorchED.Sometimes the game just needs to crash once to sort itself out and runs fine from then on. I haven't found a way around that yet. It's a bit of a disappointing outcome, but what can you do?
FIND A WAY AROUND IT! D:
If you want more information than what I've blathered on about up there, I can send you a copy