wireless network works erratically

Hello,

I have some problems, which I reproduce consistently both in Ubuntu, XUbuntu and KUbuntu.

Synthetically, the wireless network connection seems to stop working either when I switch to a different network, or when the current one goes down.
The problem can have several, but similar behavior.

For example (case 1):
 * I am connected, the connection goes down
 * I try to switch network, but the spinner of Network manager applet still continues running with the old one
 * I try to disable the wireless connection from the same applet, but the spinner still runs

Case 2, happened today:
 * I am about to connect to a wireless network for the very first time (Live CD)
 * I try to switch before the first one has been established, spinner stuck at running! (indicating an attempt to connect to the first network)
 * I disable the wireless card from the system options: spinner still running
 * I drop the applet; reenable wireless card; readd the applet: now the applet doesn't see any wireless card.

I can reproduce this problem consistently.

Key element:
 * OpenSUSE works perfectly under this aspect

My system (pretty standard):
 * Asus A8JC Notebook: Centrino duo, Intel PRO/Wireless 3945ABG Network Connection
 * [K|X]Ubuntu 7.10

Cheers,
Saverio M.