I am no expert on the subject, but it could be a problem with the card itself. A couple of months ago my dog chewed up my wireless card. I ordered a new one (AWUS036H/rtl8187) and was having the same problems you described. The card worked fine in windoze but lost funcionality every few minutes in bt3. I sent it back, and got a different one. The one I recieved as a replacement works great.