From Bjork.com

Due to circumstances outside her control, Björk has been forced to withdraw from the Wild In The Country Festival next week. Björk is extremely disappointed about this. As a result of significant problems with the event, including its staging, sound and lighting it is no longer possible for her to perform.

Geoff Oakes of Renaissance, the promoters, said yesterday regarding ticket holders who will want refunds: "We hope to be able to offer refunds to as many people as possible".