feathering error

Looking at your tutorial, it is really very out of date, these days nobody should be deleting pixels as it's a permanent modification and guessing what the feathering setting should be by trial an error is not necessary. Here is an alternative method that will do exactly the same thing but without destroying any pixels

1) Start with your image open in Photoshop

2) Make a selection-incidentally it can be elliptical or any shape

3) Press 'Q' on the keyboard to go into Quick Mask mode and it will look like this unless you have changed the default rubylith color

4) Go to the filter menu and select 'Gaussian Blur'  A feather is just a blurred edge essentially

5) Use the radius slider to soften the edge of the selection. You will be able to see visually the effects of the feather like below

6) Press Q to exit the quick mask mode and click on the marked 'layer mask' icon.

7) You can now see the effect of the feathering applied

8) Finally create a new layer and place it below the master image. Fill with your chosen color and you have your completed image with soft edges.