If this was a stain it shouldn't be flaking off. Wolman F&P Premium Wood Finish & Presservative is a transparent stain. Stains soak into the fibers and so won't flake off.
So if its really flaking off then one of three things: 1. You used something other than the F&P, ie it wasn't a stain. Perhaps you used a solid color stain? 2. Something prevented the stain from penetrating (dirt, previous finish) 3. Your deck is made of something other than raw cedar - trex or similar, perhaps the cedar was pretreated like wolmanized wood?