Try "ifconfig wlan0 down" then "ifconfig wlan0 up"
You could also try "iwlist wlan0 scan" This will scan from the command line for available AP's.
Did you try to reboot? Sometimes the network gets stuck in non working state.
Starting a particular connection is only possible for already setup connections. It works by sending commands to the connection manager, so it will probably not work if the connection manager does not work. The command is: dbus-send --type=method_call --system --dest=com.nokia.icd /com/nokia/icd com.nokia.icd.connect string:$1 uint32:0 where $1 is replaced by the id of the connection
(find it by running the command: gconftool-2 -R /system/osso/connectivity/IAP | less
I remember this. This sounds a bit like what happened to me when trying to upgrade Diablo with apt-get. The install process (using apt-get instead of the Application Manager) runs out of space, and leaves the tablet in a broken state, with more packages to install, but unable to connect to the Internet to finish the upgrade. But this might not be the same thing at all; I've never heard of anyone upgrading from Chinook to Diablo via the command line.