DLINK DWL-122 on ARM platform not stable, why?

The dlink dwl-122 dongle i used on my ARM(XScale270) platform seemed
not stable, the linux is 2.6.10. USB driver used OHCI mode.

1. opensystem without WEP
After a set of wlanctl-ng command and iwconfig, ifconfig, route...,
the output listed below:
/ # linkstatus=CONNECTED
hfa384x_usbctlx_complete_sync: CTLX[3] error: state(Request failed)
prism2sta_commsqual_defer: error fetching commsqual

Around 2 seconds after "linkstatus=CONNECTED", the first error appeared.
And when i ping the gateway, another error come out like below:

/ # ping 192.168.0.1
PING 192.168.0.1 (192.168.0.1): 56 data bytes
64 bytes from 192.168.0.1: icmp_seq=0 ttl=127 time=9.9 ms
64 bytes from 192.168.0.1: icmp_seq=1 ttl=127 time=3.6 ms
hfa384x_usbctlx_complete_sync: CTLX[3] error: state(Request failed)
prism2sta_commsqual_defer: error fetching commsqual

Sometime, this error appeared:
skb_p80211_to_ether: OTHER frame too large (-4 > 1500)
hfa384x_usbctlx_complete_sync: CTLX[3] error: state(Request failed)
prism2sta_commsqual_defer: error fetching commsqual

Will you please give me some guide? How could I make it stable? What's
the reason of those errors?

2. Opensystem with WEP(64bits)
When i set WEP(64bits) on AP, the dongle also could connect to the AP,
and i could see the dongle's information on AP's trace. But even i set
IP address and route of the dongle, no host could i ping to. Some
error info like this:
... ...
message=lnxreq_autojoin
  ssid='mobot'
  authtype=opensystem
  resultcode=success
/usr/lib # linkstatus=CONNECTED

error message shown below:
hfa384x_usbctlx_complete_sync: CTLX[3] error: state(Request failed)
prism2sta_commsqual_defer: error fetching commsqual
... ...
I never really connected to LAN when my AP set WEP.

I need some guide on these problems, thank you very much!

Tiger.Yin