How to make Enemies

[The chaser]

Ok, here i go. I'm using blender, and i still have to know well how does it work. I tried to:
1: Import the brute
2: With edit mode, i got some edges of it's sword and i moved them, so it seems an axe, and I exported it as a .dae (with another name, of course)
Then, i went to Model editor and I tried to import the mesh. It crashed. I know that modeling is very hard, but for my CS i would like to have a bit different character.
I think that it is a texture problem, but i'm not sure.
I don't exactly know if i'm asking too much, but i want to do something for beggining. Perhaps i should begin with desks, or something, but i'm not really interested on furniture.