If you are experiencing peeling, you painted rather than stained. I don't have too much respect for solid color stain when an opaque film finish is desired. An adhesion failure is usually due to what was on the surface before. If the house was originally finished with an alkyd oil stain, these can leave a "live" oil finish that is very difficult to cover without using high quality stain blocking primer. More information on the siding history, and what you used is needed to answer.