Partial Selection Problem

I create i new image with standard properties like 400x400 and 72dpi with a background color. Then i create a new layer and want to make a selection on the new layer using the Elliptical Marquee Tool.
When i do this i get the error beneath:

Warning: No pixels are more than 50% selected. The selection edges will not be visable.

I doesn't matter which size the selection has, i always get this message.

I just started to learn photoshop, but i can't figure this out :(

ok stupid me.... some day i enter 200px for the option Feather :p