Problems with Atheros 108Mbit cards

Hi,

I recently bought a Netgear WG511T. However the connection always breaks down 
after a few seconds. It worked fine with an Atheros 54 Mbit chip before and I 
haven't changed the config. 
I can see a valid turbo mode via ifconfig -m ath0. But if I run wpa_supplicant 
manually I shows the following output:

wpa_supplicant -i ath0 -d -c /etc/wpa_supplicant.conf
Initializing interface 'ath0' conf '/etc/wpa_supplicant.conf' driver 'default'
Configuration file '/etc/wpa_supplicant.conf' -> '/etc/wpa_supplicant.conf'
Reading configuration file '/etc/wpa_supplicant.conf'
ctrl_interface='/var/run/wpa_supplicant'
ctrl_interface_group=0 (from group name 'wheel')
Priority group 0
   id=0 ssid='DA-BUTZE-COE'
Initializing interface (2) 'ath0'
Own MAC address: 00:0f:b5:26:a9:e5
wpa_driver_bsd_set_wpa: enabled=1
wpa_driver_bsd_set_wpa_internal: wpa=3 privacy=1
wpa_driver_bsd_del_key: keyidx=0
wpa_driver_bsd_del_key: keyidx=1
wpa_driver_bsd_del_key: keyidx=2
wpa_driver_bsd_del_key: keyidx=3
wpa_driver_bsd_set_countermeasures: enabled=0
wpa_driver_bsd_set_drop_unencrypted: enabled=1
Setting scan request: 0 sec 100000 usec
Using existing control interface directory.
Starting AP scan (broadcast SSID)
Received 0 bytes of scan results (1 BSSes)
Scan results: 1
Selecting BSS from priority group 0
0: 00:0f:b5:e7:17:90 ssid='DA-BUTZE-COE' wpa_ie_len=24 rsn_ie_len=0
   selected
Trying to associate with 00:0f:b5:e7:17:90 (SSID='DA-BUTZE-COE' freq=2437 MHz)
Cancelling scan request
Automatic auth_alg selection: 0x1
WPA: using IEEE 802.11i/D3.0
WPA: Selected cipher suites: group 8 pairwise 8 key_mgmt 2
WPA: using GTK TKIP
WPA: using PTK TKIP
WPA: using KEY_MGMT WPA-PSK
WPA: Own WPA IE - hexdump(len=24): dd 16 00 50 f2 01 01 00 00 50 f2 02 01 00 
00 50 f2 02 01 00 00 50 f2 02
No keys have been configured - skip key clearing
wpa_driver_bsd_set_drop_unencrypted: enabled=1
wpa_driver_bsd_associate: ssid 'DA-BUTZE-COE' wpa ie len 24 pairwise 2 group 2 
key mgmt 1
wpa_driver_bsd_associate: set PRIVACY 1
Setting authentication timeout: 5 sec 0 usec
Association event - clear replay counter
Associated to a new BSS: BSSID=00:0f:b5:e7:17:90
No keys have been configured - skip key clearing
Associated with 00:0f:b5:e7:17:90
Setting authentication timeout: 10 sec 0 usec
RX EAPOL from 00:0f:b5:e7:17:90
Setting authentication timeout: 10 sec 0 usec
IEEE 802.1X RX: version=1 type=3 length=95
  EAPOL-Key type=254
WPA: RX message 1 of 4-Way Handshake from 00:0f:b5:e7:17:90 (ver=1)
WPA: Renewed SNonce - hexdump(len=32): 56 11 5b 20 7a fe 58 40 bd de 36 94 b3 
10 4b 02 74 eb 76 22 6e e4 c8 c6 1f fc 58 76 6a 11 12 de
WPA: PMK - hexdump(len=32): [REMOVED]
WPA: PTK - hexdump(len=64): [REMOVED]
WPA: EAPOL-Key MIC - hexdump(len=16): 21 59 6d c1 21 5a 8d 7a 84 c7 bc 3e e0 
23 ee f8
WPA: Sending EAPOL-Key 2/4
RX EAPOL from 00:0f:b5:e7:17:90
IEEE 802.1X RX: version=1 type=3 length=95
  EAPOL-Key type=254
WPA: RX message 1 of 4-Way Handshake from 00:0f:b5:e7:17:90 (ver=1)
WPA: PMK - hexdump(len=32): [REMOVED]
WPA: PTK - hexdump(len=64): [REMOVED]
WPA: EAPOL-Key MIC - hexdump(len=16): 0c b4 7f 79 85 a6 c5 dd 6a 6b a7 7d 47 
83 77 81
WPA: Sending EAPOL-Key 2/4
RX EAPOL from 00:0f:b5:e7:17:90
IEEE 802.1X RX: version=1 type=3 length=95
  EAPOL-Key type=254
WPA: RX message 1 of 4-Way Handshake from 00:0f:b5:e7:17:90 (ver=1)
WPA: PMK - hexdump(len=32): [REMOVED]
WPA: PTK - hexdump(len=64): [REMOVED]
WPA: EAPOL-Key MIC - hexdump(len=16): c7 77 0c 48 71 d8 b2 7e 1e 7f 64 fb eb 
3c 26 51
WPA: Sending EAPOL-Key 2/4
RX EAPOL from 00:0f:b5:e7:17:90
IEEE 802.1X RX: version=1 type=3 length=95
  EAPOL-Key type=254
WPA: RX message 1 of 4-Way Handshake from 00:0f:b5:e7:17:90 (ver=1)
WPA: PMK - hexdump(len=32): [REMOVED]
WPA: PTK - hexdump(len=64): [REMOVED]
WPA: EAPOL-Key MIC - hexdump(len=16): cc 40 2b 73 50 b3 21 e5 85 f3 1c 48 45 
e9 3a 35
WPA: Sending EAPOL-Key 2/4
Setting scan request: 0 sec 100000 usec
Added BSSID 00:0f:b5:e7:17:90 into blacklist
Disconnect event - remove keys
wpa_driver_bsd_del_key: keyidx=0
wpa_driver_bsd_del_key: keyidx=1
wpa_driver_bsd_del_key: keyidx=2
wpa_driver_bsd_del_key: keyidx=3
wpa_driver_bsd_del_key: addr=00:00:00:00:00:00 keyidx=0
ioctl[SIOCS80211, op 20, len 7]: Can't assign requested address


And after that last message the connection breaks down again... thanks for any 
help.

Jochen