When using this model you should import 3 files.
RPGHeroVillager.mdx
RPGHeroVillager_Portrait.mdx
RPGHeroVillager.blp
Looking at the original post that the file came from, partway down you see a section that reads:
Import the skins to the following paths:
Textures\RPGHeroVillager.blp
That means that you need to click the 'use custom path button' ONLY on the /blp file, so in the end if you looked at the 3 paths for the files, they would read:
textures\RPGHeroVillager.blp (modified the war3mapimported part)
war3mapImported\RPGHeroVillager.mdx (not modified in any way)
war3mapImported\RPGHeroVillager_Portrait.mdx (not modified)
after that the model should show up in-game just fine.
Fixed version attached.