wireless sniffing network problem

[Lucide]

Hi,

I have a setup where I have a laptop running backtrack and am connected on a wireless network where there is 2nd wireless computer and a computer wired with lan. I can succesfully sniff the lan computer which is on 192.168.1.67 but when I follow exactly the same steps to get the traffic from the wireless computer 192.168.1.65 nothing comes in. Also trying to capture all traffic in the network will only bring up the lan computer's traffic. Can someone give me some tips or advice if I do something wrong? I tried some extended search here and on google and tried many different sniff approaches but nothing seems to work.
I'm booting from usb.

Thanks for any help.