Out of all the possible answers, I suspect you’d not have said ‘label troubles?’
EMI is dicking Danger Mouse around and now it seems that the album will never be released. That’s not stopped the project entirely, though.
Dark Night of the Soul was originally intended as a book of photographs by David Lynch, accompanied by Sparklehorse and Danger Mouse’s music. Via the project’s website, the book (before the limited-edition run ran out) comes with a blank CD bearing the instructions “use it as you will”.
A stream of the whole album is available at NPR.org. It features a massive shwag of guest artists: Frank Black, The Flaming Lips, Iggy Pop, Suzanne Vega, David Lynch (oh dear?), Gruff Rhys and more.