I have been having the same problems in the Dapper (stable) release. I've been using various bash scripts to fix the routing problems. I installed the 'wffi-radar' wifi manager and it worked right off. No more scripts. I would suggest that you look at how 'wifi-radarr' solved these problems.
-- wireless assistant does not connect in edgy https://launchpad.net/bugs/64841 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs