I had exactly this problem, and fixed it with the asoundconf set-default-card <1 line of output of asoundconf list>
-- Dist-upgrades from Dapper to Edgy break on existing ~/.asoundrc.asoundconf due to missing conf parameters (e.g., Unable to find definition 'defaults.pcm.ipc_key') https://launchpad.net/bugs/67998 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
