Running this card in backtack 4 vmware image downloaded off this site.

My problem is that when attempting to crack my network (WEP) my data rate increases real slow, 1 0r 2 data here and there. somethings wrong and i cant figure it out. i used to have the 500mw card and ran it on backtrack 3 and was getting 500 ivs ps roundabout. also tried it on backtrack 4 live cd still the same, very slow data rate. card is basically plug and play right? any drivers i need to install to get it right?

If anyone can point me in the right direction id thank you.