Cannot connect to a wireless network via command line.

[Aston <true aston yahoo com cn>]

Hi all,
My laptop unable to connect to a particular wireless network(essid:
"ChinaNet-Starbucks" , it is a open wiwiz hotspot  http://www.wiwiz.com) by using
NetworkManager, so i swith Connection Mode to 'ifup' through YAST,then i encounter
such a situation:
----------------------------------------------------------------------------
diversity:~ # ifconfig wlan0
wlan0     Link encap:Ethernet  HWaddr 00:22:FA:43:30:68  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:35491 errors:0 dropped:0 overruns:0 frame:0
          TX packets:27670 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:25311487 (24.1 Mb)  TX bytes:4352412 (4.1 Mb)

diversity:~ # iwconfig wlan0 essid "ChinaNet-Starbucks"
diversity:~ # dhclient wlan0
ls: cannot access /var/run/netconfig//wlan0/: No such file or directory
----------------------------------------------------------------------------



My laptop configuration:
----------------------------------------------------------------------------
Thinkpad t400 2767 cto, cpu T9550
OS: openSUSE 12.2 64bit GNOME
wireless card: Intel PRO/Wireless 5100AGN 
----------------------------------------------------------------------------

iwlist wlan0 scan：
----------------------------------------------------------------------------
          Cell 03 - Address: 38:22:D6:7F:70:31
                    Channel:1
                    Frequency:2.412 GHz (Channel 1)
                    Quality=61/70  Signal level=-49 dBm  
                    Encryption key:off
                    ESSID:"ChinaNet-Starbucks"
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
                              11 Mb/s; 12 Mb/s; 18 Mb/s
                    Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
                    Mode:Master
                    Extra:tsf=0000025ffeaddd4c
                    Extra: Last beacon: 85ms ago
                    IE: Unknown:
00124368696E614E65742D537461726275636B73
                    IE: Unknown: 010882848B0C12961824
                    IE: Unknown: 030101
                    IE: Unknown: 0706434E49010D16
                    IE: Unknown: 2A0100
                    IE: Unknown: 32043048606C
                    IE: Unknown:
2D1A4C101FFFFF000000000000000000000000000000000000000000
                    IE: Unknown:
3D1601080400000000000000000000000000000000000000
                    IE: Unknown:
DD180050F2020101800003A4000027A4000042435E0062322F00
                    IE: Unknown:
DD1E00904C334C101FFFFF000000000000000000000000000000000000000000
                    IE: Unknown:
DD1A00904C3401080400000000000000000000000000000000000000
----------------------------------------------------------------------------

thanks.
--
True Aston