Hmm i think there is one problem with the kernel (i have the same issue with ubuntu and atheros chipset. I posted bug report http://bugs.launchpad.net/ubuntu/+so...ux/+bug/530449)
Aircrack-ng can not capture data packet, only frames. You can see it also on screenshoot posted at the begining of this topic. Lot of network and no single data packet - impossible

as far as i remember it was possible to capture a data packet on channel 6 in stock kernel, i can't confirm it now cause there is no channel 6 network around.

-------------------update------------

ok i have checked this again using easy debian and aircrack.
I'm able to sniff data at unencrypted networks(didn't saw it before cause i have poor signal to unencrypted networks in my area)
whean i was trying to generate some traffic at my wpa2 network data packet does not increasing. But i can see data packet in wireshark but they are apear as malformed. Data packet don't have a source MAC adress - that is why aircrack doesn't see them (in the same time my debian lenny on pc can see the same packets source MAC adress and aircrack data packet count goes up

screenshot: