Tamiroquai’s issue was solved here, but it was a different wireless adapter model anyway.
mp3gus, I see that your Ruckus* APs are concurrent dual band capable; perhaps you may want to try connecting the wireless adapters to the 5 GHz band. Whether it is choosing the preferred network band (2.4 or 5 GHz) or forcing the wireless mode (802.11a) this is an option that you may try as well, so the wireless adapter will connect to one specific band only. Let me know if this helps.