In reply to Flinticus:
I had a pair of Scarpa's that did the same. You could try giving them, but I think it's basically a fault with the sole unit, with the softer core disintegrating. I didn't bother trying to repair, as I could scrape the core apart with a fingernail, and figured it would just fail again very soon.
It's a vibram sole unit. I should have got in touch with Scarpa as they hadn't really had a lot of use, but I never bothered.