What has happened to my stain???

Below is either my picture or a link to it. This is the deck of my homebuilt boat it has been under tarp all winter. Today when I uncovered part of it what you see is what i found. It was stained with Chris Craft Walnut stain from Sandusky Paint and varnished with 10- 12 coats of Admirals Gloss varnish from West Marine. The finish is still there but the stain is gone… needless to say I’m a little annoyed at having to sand it back down and start over. I just want to prevent it from happening again!
[url]http://www.flickr.com/photos/35500228@N08/3281469079/