problems on ARM9 linux-wlan-ng driver

I tried linux-wlan-ng on my ARM9(Intel PXA270) platform with two types of dongles: d-link dwl-122 and netgeer MA111, but the same problems exists:

1. within an opensystem (no WEP), the dongle could connect to AP, but the connection was very unstable. And while it lost connection, it couldn't resume itself auto.

2. with a WEP opensystem, the dongle couldn't connect to AP even I set correct params.

Will somebody please give me a little guide? Thank you very much!