Your skinning is probably not perfectly clean,
the vertex in the bottom seem to not be skinned properly to a bone.

I would need assistance with a mesh problem.

In blender my model looks like this:

http://tinypic.com/view.php?pic=nlwodj&s=6

But in maratis it has some wierd spike from the bottom:

http://tinypic.com/view.php?pic=qrlvgx&s=6

Why so?

I put the file up here too: http://www.uploadmb.com/dw.php?id=1365521870