I upgraded Custom Permalinks from 0.6.1 to 0.7 and discovered that all my pages and posts with custom permalinks had disappeared. This may be because my site address (in General Settings) http://www.gentlewisdom.org.uk is different from my WordPress address http://www.gentlewisdom.org.uk/wordpress. My custom permalinks were all of the form http://www.gentlewisdom.org.uk/about-peter-kirk/. But on upgrading they had all been changed in the Custom Permalinks list to the form http://www.gentlewisdom.org.uk/wordpress/about-peter-kirk/, and worse still users were getting 404 errors for both of these URLs. When I tried to edit the pages the only permalinks I was offered started http://www.gentlewisdom.org.uk/wordpress/ and there was no way to delete the unwanted wordpress/.
I deleted 0.7 and reloaded 0.6.1, and the problem immediately went away.
This looks like a serious bug needing immediate rectification.