Problem when exporting from Blender to Unity 3D? I'm having a problem when trying to import my character to the Unity Engine. It gives me message: 

Unable to open Assets/untitled.fbx: Check external application preferences

Can anyone please tell my what's wrong and how to fix it?

I followed the steps from a tutorial I watched: I exported my character as a .fbx file and unchecked Include Default Take, but it doesn't work.
The Blender exporters sometimes don't work perfectly. However, Unity supports .blend files, so you can simply drag and drop the .blend file into the Unity project.