I'm following the answer of this question: Make a 3D tube with a Bézier curve?
Now i set the bevel of the curve larger and the curve becomes higher. But there is no tube. It's just flat.
The same thing happens when I used this tutorial: http://wiki.blender.org/index.php/Doc:2.4/Tutorials/Modeling/Curves/Making_A_Tube
Here is an image of the problem i face:
It's not a tube.
Edit: Blender file: http://www.pasteall.org/blend/40010