shadow not rendering This is driving me insane ! 

I have been making a simple scene for a point&amp;click game. Most of the models are 'done', and I now want to set up the lighting.
I am using Toon shaders for my models. I have added 1 hemi lamp, and 1 sun in my scene. 

When I look through the camera, in the editor, I can see shadows in the sofa (left img). When I render the scene (Blender internal) there are no shadows (right img). And why is there such a difference in the way the scene looks ?

What settings could I inadvertently have changed ???
I have been trying to fix this for 2 days already ... I am getting desperate  :-)

Thanks for your help !
I know this is an old question, but -- 

are you sure you have shadows turned on in the render panel?

Under the render panel (the one with the little "camera" icon), scroll down to the "Shading" roll-out, and be sure you have "Shadows" checked. 

Otherwise your shadows won't render.

Shadows are a two-step thing.  Once you've refined them in your lighting panel, be sure to turn them on in your render panel.