The website has basic details of the festival - http://www.angelfire.com/planet/doncasterfolk/ and phone numbers of organisers. As I understand, indoor camping could still be arranged (though the original venue fell through). There is space for campervans / caravans, but ring first. I'm sure tickets will still be available.
Late confirmation of funding is a perennial problem for smaller festivals; but especially so for those early in the year when there isn't the opportunity to "pass the word around" in the weeks before.
P.S. Anyone feeling the compelling urge to reward the morris dancers' efforts will will find a warm welcome in the Mason's Arms on Saturday lunchtime. Cheers! R.