network manager drops wireless connection after update

I am using Ubuntu 8.10 Intrepid Ibex, with all updates current to July 26th, 2008. My wireless internet connection always connects to the correct network but about every five minutes it drops out. I've done some inspecting and several interesting things come up in /var/log/syslog. It seems that about every five minutes the connection seems to reauthenticate. There are three other computers on this network none of which are having this problem so it must be related to my network card drivers or network manager itself. Here is the output of lspci -vv:

00:09.0 Ethernet controller: Atheros Communications Inc. AR5212/AR5213 Multiprotocol MAC/baseband processor (rev 01)
 Subsystem: AMBIT Microsystem Corp. Device 0406
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 168 (2500ns min, 7000ns max), Cache Line Size: 128 bytes
 Interrupt: pin A routed to IRQ 11
 Region 0: Memory at 48000000 (32-bit, non-prefetchable) [size=64K]
 Capabilities: [44] Power Management version 2
  Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 PME-Enable- DSel=0 DScale=2 PME-
 Kernel driver in use: ath5k_pci
 Kernel modules: ath5k

Here is the output of iwconfig ath0:

ath0 IEEE 802.11 ESSID:"2WIRE486"
          Mode:Managed Frequency:2.417 GHz Access Point: 00:1D:5A:77:1F:09
          Bit Rate=24 Mb/s Tx-Power=27 dBm
          Retry min limit:7 RTS thr:off Fragment thr=2352 B
          Link Quality=65/100 Signal level=-55 dBm Noise level=-97 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

The weird part being that if I right-click on nm-applet and select connection information it gives me a different bit rate. These never match. I tried to create a script to force the bit rate on login but it seems to only affect nm-applet and iwconfig reports its own bit rate. I find this extremely weird because i use iwconfig ath0 rate 54M in the script to force the bit rate. nm-applet now reports 54Mb/s but obviously iwconfig does not agree. This is very irritating. This is the first problem Ive ever had with ubuntu that I feel can't be fixed with a work around. I believe this either to be a problem with network-manager or linux-restricted-modules.