Can you please post the map here as an attachment so I can see if it crashes for me? If you haven't imported a custom model or skin (that's what I meant by texture) that Thrall or Cairne are using then it honestly sounds like your game install is corrupted in some way. I would uninstall and reinstall wc3, then update by going on Battle.net (it will probably be updated automatically if you're using the downloadable game installers from the Blizzard store, but just to be safe).
war3.mpq
War3Patch.mpq
War3x.mpq
War3xlocal.mpq
Yes those are the file archives that I was talking about. They are what hold all the default model files, textures, icons, UI elements, etc. for the game so that you don't have to redownload that data as part of every map that uses default wc3 data. In recent versions of wc3 the .mpq file format was deprecated and replaced with the .casc file format, which functions essentially the same but requires different tools to view/extract from.
This program can view and extract from CASCs, and there are many other MPQ viewers here in the
Tools section.
If reinstalling doesn't fix the crash then you can try overwriting the models/textures with one extracted from a non-crashing install and see how that works. I'll post mine if it comes to that. The
only reason you wouldn't want to wipe and reinstall now is if you are running an older wc3 patch that you need to use for development for compatibility reasons. Once you update you can't downgrade and finding full installs of previous patches online is time consuming and frustrating. I only say to think about this since you found the mpq files which implies you're on an old patch.