Oops, sorry folks. I had to head out the door and forgot to provide that info.
Slackware 14.0 32-bit. Thinkpad T400. According to lspci:
Network controller: Intel Corporation PRO/Wireless 5100 AGN
I have no problems connecting with wireless with no encryption. I've been running that way on my own home router since I adopted this laptop a couple of months ago. Now I'm at another person's house and we're trying to connect the laptop to his router that uses encryption. His Windows Vista laptop connects without issue.
Despite my newbie status with laptops and wireless, I doubt the problem is the driver. The logs imply an authentication problem --- kind of like NM is sending the PIN but in an incorrect manner.
With the logging adjustments, and using nm-applet, I see the following in syslog:
NetworkManager: <warn> Activation (wlan0/wireless): association took too long.
NetworkManager: <warn> Activation (wlan0/wireless): asking for new secrets
NetworkManager: <warn> Couldn't disconnect supplicant interface: This interface is not connected.
NetworkManager: <warn> No agents were available for this request.
NetworkManager: <warn> Activation (wlan0) failed for access point (w-pc)
NetworkManager: <warn> Activation (wlan0) failed.
And in wpa_supplicant.log, way, way too much information to post, but I see entries about "4WAY_HANDSHAKE -> DISCONNECTED" and "WPA: 4-Way Handshake failed - pre-shared key may be incorrect."
The router had WPS enabled, but we tested disabling that option with the same failed results.