Hi, Im new to the forum, and I have a trouble with my alfa 500mw using it with airodump-ng in ubuntu and I can't get PWR readings, Im siting with the adapter next to my router and this it a reading I get, (where my essid is "Sammy")

BSSID PWR Beacons #Data, #/s CH MB ENC CIPHER AUTH ESSID
3E:19:5E:B5:2F:E9 0 3 0 0 11 54e. WPA2 CCMP PSK <length: 8
00:19:5E:B5:2F:E9 0 6 0 0 11 54e. OPN HotZone Duo
06:19:5E:B5:2F:E9 0 3 2 0 11 54e. WPA2 CCMP PSK regcag
00:06:25:F0:4C:C5 0 25 0 0 6 11 WEP WEP Sammy

What could be the problem?, I've downloaded latest drivers also.
In backtrack 3 it works perfect, I can Inject and fake auth but in ubuntu is hopeless without good PWR readings. anyone can help me?
thanks