I see from your description that you are using ProSet to run your adapter. I cannot give specifics for that unfortunately, so I can only suggest the WinXP/WZC equivalent, which would be academic in your case. In essence, you may need to prevent your adapter from using and/or accepting ad-hoc links.
On a related note, are you aware of how quickly and easily WEP can be cracked by anyone with a modicum of knowledge and some freely available software? Between 3 and 5 minutes, typically. If your neighbourhood is populated by WPA networks, or has a dearth of networks altogether, you could be an easy target.