Comment 21 for bug 365321

It's the same problem with ath5k and seem that happen with many others wireless cards. Isn't a Ubuntu problem, in Archlinux i have the problem too.

The problem is easily reproducible:
You connect to a network, then disconnect, and finally, try to connecting again. Wicd just say: "Unable to obtain IP Address"

There is a workaround (rough-and-ready) if you reload the kernel module of the wireless interface with rmmod (or modprobe -r, it's the same) and then modprobe. This is the reason because many of you have to reboot the computer, but just need reload the module.

In the bugtracker of Archlinux (http://bugs.archlinux.org/task/18011) they say that is a kernel problem, i don't know. But that i know is that other networks manager don't have this problem just with wicd.