Whilst in Blender; when exporting, do you have it limited to selected objects or are you just exporting the whole scene as an fbx? You said you were getting an error so It may be a converter issue. I'm still new to this so DO NOT take my word as law. I know a good amount about blender, but not the mod tools. Personally I don't think it's a Blender problem, it could be the conversion process. I'd say check your export settings in Blender though just in case, see if you're exporting your applied scaling to "fbx unit scale" all of that stuff. And check to see if your model is properly parented to your skeleton.