Anyone knows what "assoc failed (reason 51)" means?

Question

Hi all.
I have a MacBook Pro 17 late 2007 (MacBookPro 3,1). It has a Atheros wifi card (AR5418).
I have issues connecting to a WPA2 Personal 802.11n netowork. I manage to connect to other wifi networks and other computers connect to that network (even other macs) but not the MacBookPro 17. Doing a wifi debug I logged the following:
Mon Feb 27 17:57:02 <kernel> RSNSupplicant: Releasing authenticator for 00:00:00:00:00:00
Mon Feb 27 17:57:02 <kernel> en1: Terminating supplicant.
Mon Feb 27 17:57:02 <kernel> ieee80211_init_node[1132] old_auth 5
Mon Feb 27 17:57:02 <kernel> [00:90:7f:83:80:52] send station deauthenticate (reason 3)
Mon Feb 27 17:57:02 <kernel> __ieee80211_newstate: ASSOC -> INIT (arg 0xffffffff)
Mon Feb 27 17:57:02 <kernel> [00:90:7f:83:80:52] assoc failed (reason 51)
Mon Feb 27 17:57:02 <kernel> __ieee80211_newstate: AUTH -> ASSOC (arg 0x0)
Mon Feb 27 17:57:02 <kernel> [00:90:7f:83:80:52] recv auth frame with algorithm 0 seq 2
Mon Feb 27 17:57:02 <kernel> setPMK: PMK SET!
Mon Feb 27 17:57:02 <kernel> initWithInterfaceAndIE: _myMacAddress 00:1e:52:6f:a4:fc
Mon Feb 27 17:57:02 <kernel> parseRSNIE: groupCipherType = 3 pairwiseCipherType = 5 authSel = 2
Mon Feb 27 17:57:02 <kernel> scan_next: done, [ticks 803677, dwell min 8 scanend 823589]
Mon Feb 27 17:57:02 <kernel> ieee80211_cancel_scan: cancel active scan
Mon Feb 27 17:57:02 <kernel> __ieee80211_newstate: JOIN -> AUTH (arg 0xc0)
Mon Feb 27 17:57:02 <kernel> __ieee80211_newstate: SCAN -> JOIN (arg 0x0)
Mon Feb 27 17:57:02 <kernel> ieee80211_init_node[1132] old_auth 5
Any one knows what "reason 51" means in the line Mon Feb 27 17:57:02 <kernel> [00:90:7f:83:80:52] assoc failed (reason 51)?
I googled but found nothing on that particular reason code. Is there any documentation on reson codes from Apple?

Answer 1

SOLVED the hard way: by changing the Wifi card.
I replaced the 3 antennas Atheros card with a spare BCM94321MC I removed years ago from a 1st generation AppleTV (to install a CrystalHD full HD video card).
Googling I found that BCM94321MC is the standard AirPort mounted on early 2008 MBP 17 (model A1261) which came out just after my mid-2007 MBP 17 (A1229). The doubt I initially had was that BCM94321MC has 2 antenna connectors as opposed to the 3 antennas my MBP has, but I found on a disassembly picture posted by iFixit that model A1261 mounts BCM94321MC the card using a 3 wire antenna simply leaving the gray wire disconnected.
(http://www.ifixit.com/Guide/Image/meta/NWjHlDGSULFukQCS)
As soon as I replaced the card every network issue disappeared.
Since BCM94321MC is used by a more recent MBP model I'm confident that future OSX updates for my MBP will support the WIFI card.
To recap: After introducing 3 antennas Atheros cards in A1212 and A1229 models, Apple switches back to the 2 anteanns BCM4321MC cards in A1261 leaving the same 3 wire antenna with 1 wire disconnected. Sounds like a quick and dirt fix to me, probably the 3 antennas design in combination with the Atheros card, the MBP or both was bogus.