From ActiveSkin website: http://www.softshape.com/software/develop/
ActiveSkin status
We’re sorry for inconvenience, but ActiveSkin downloads and purchase are not available for a moment. We continue our registered users support without interruptions, please contact us for further information. For updated information about ActiveSkin availability, please visit our website shortly.
Does this mean that users can’t develop new skins anymore? ???
Will it be changed for another product, I mean, by Alwil skin developers (Martin)?
I’m afraid ActiveSkin is unavailable for quite some time already.
I am also afraid that it’s rather hard to change for another product, as I’m not sure if there is any other similar product (and even if there was, it would probably mean recreating all existing skins from scratch, and also rewriting a lot of code in the user interface part).
So this is the death of new skins :‘( :’( 
Presumably not, for those who have a copy of ActiveSkin, e.g. all those who have already built avast skins presumably kept their copy.
So it may not be the end of new skins, probably more importantly is having people with the time skill and inclination to build a new skin.
I am interested in making new skin, but it seems I will have no way to do this no matter how much I want.
Since they are no longer selling it, perhaps someone who already has it can give it to someone else? Will have to talk to SoftShape about it though I suppose.
Well a quick search for ActiveSkin returns many hits some for downloads, http://www.google.com/search?q=ActiveSkin.
http://www.topshareware.com/ActiveSkin-download-80.htm.
Though I don’t know if having downloaded it (it costs $99) you will be able to pay if as you say the purchase isn’t available.