Also; the game can randomly mess up and crash or just not start after running it for awhile or opening and closes it a lot, or even just running it once and leaving your PC on for a long time before you run it again.
Errors like this usually say a animation can not be found (even though it does exist and works), like so;
It can also do this for many other files of all sorts as well. It does not always show an error however, or may show something that doesn't relate, restarting your PC is necessary to resolve these. So maybe this battle crash problem has some similarities to the above random problem.
19:04:24.934 [system.io] [trace] file open,,mods/Third_Age_3/data/animations/MTS2_Troll_Mace/MTW2_Mace_advance_to_combat_jog.cas,,not found
19:04:24.934 [system.io] [warning] open: mods/Third_Age_3/data/animations/MTS2_Troll_Mace/MTW2_Mace_advance_to_combat_jog.cas is missing