Animation Issue

I am very new to skinning & this is really my 1st experiance. I am trying to do a simple animation to see how it works. i make the skin & when i install it into the folder & go to choose it i get this error- Masks are currently not supported. Please apply the mask to the layer & try again. Mask found on layer: </Layer set>.
there is nothing on that layer in my skin or the tut3 example which loads fine. Thanks for any help i can get. 

