Need some help with a scaling problem.

Hello!

I have made circles from an image via the imagesampler. (Based on a script I found in the Gallerysection). Then I have tried to map it to a surface. However when I map it to my surface the circles becomes ellipses. So I wonder if somebody knows how I could map the circles on to a surface (preferable 4 surfaces on the same time so the circles "overlap" at the corner of the surfaces) and keep the circular shape of the objects that are mapped onto the surface.