You need to cenvert the exported .blp textures into the .tga format, the Art Tools will automatically reconvert them back into .blp when u export the model!
u need the mdx pather (there are other ways to achieve the same, but this program is the easiest and fastest way to do it) get it over at wc3c, maybe its here in the tools section, too?
if u use ingame textures u need to set the texture's pathes to the exact same as in the .mpq (check those pathes with wc3viewer again)
if u use custom textures probably the path of the textures will be just xyz.blp with nothing standing before it!
because Magos ME is no official blizz tool and was made completely from scratch...
you may want to recheck the animations in the wc3viewer?
but if u want to be sure how it looks ingame u need to import it into a testmap and run it!
also, why should one dl 3dsmax illegally, if u can use gmax, which is almost the same, but for free and use BinkBoi's NeoDex script?