Hi Um? - you should have left the mould as this is as a result of the natural yeast fermenting the fruit and forms a cap that allows the liquor below to develop into the wine. the mould is removed before you rack the wine. The recipe you have sourced also uses no extra yeast to ferment the fruit plus no pectin to break the fruit down - and doesn't say you must remove the stones.... Also there are no comments about racking the wine or maturing - Damson - or almost any fruit wine - takes about a year before you can tolerate it to drink.....
If you haven't made wines before this isn't perhaps the best starter for you. Read the following Damson Wine recipes from the Yobrew site:
http://www.yobrew.co.uk/damson.php and these will hopefully point you in the right direction.
This guy also has put a lot of info on fruit fermentation onto his site which is also handy and worth reading to get an idea of what is happening to the brew:
http://home.btconnect.com/ntruman/wine/method. html
Don't foregt that all the equipment must be sterilised before you use it and you have to take care with the fermentation - don't allow the gases to build up or you get bursting bottles / demi-johns etc, so if in any doubt, off to your local home brew shop and just pick their brains - most of these shops are more than happy to help with sadvcie to the homebrewer. It should get you started on the road to trying some of the other recipes - soon be on the home made saki then..?
Have fun..!