Upgraded to 10.5.3 and then no more Airport - HELP !

Question

Hello,
I have WIFI LAN access issue after upgrading an IMac G5 to from Tiger to Leopard, and would appreciate your help.
ISSUE :
Prior to Leopard, this IMac worked on 10.4.11 with access to my WiFi AN via an Airport Extreme Card.
After I installed Leopard 10.5 straight out of the DVD :
the Airport icon on the menu bar is grayed out as if it did not pick any signal, although I did not change location nor LAN settings
when I want to access to the LAN, it requests the 24 characters WPA password, but although I know the password is correct, I get a “connection failure” or “connection timeout” error message.
I get the same messages when I try to configure access from the Network preference pane.
A a result, I cannot get nor on my LAN, nor on Internet from the G5 iMac.
UPGRADE HISTORY AND SOLUTION ATTEMPTS
I performed a simple upgrade from the DVD (ticked off the X11 option and languages translations though).
Then I also reinstalled the Airport Extreme Software form the CD, in case Leopard “erased” an Airport Extreme driver...
I also reinstalled Leopard with an “Erase” of the Hard drive,
to have a full clean start...
Last, I upgraded the system to 10.5.3 with the combo update that I downloaded from another computer, hoping that I would resolve this possible issue.
I tried to find firmware updates, but no success...
SYSTEM DESCRIPTION
This is a LAN for home use for 3 Macs :
my Mac a Dual G5 1.8 MhZ under 10.4.11, works OK. I did not upgrade.
my wife iMac Intel Core 2 Duo 1.83 MhZ, upgraded to OSX 10.5.3, works OK
my kids iMac G5, bought second hand with Tiger, does not connect after 10.5 upgrade. I bought back then also an Airport Extreme card and updated the Airport Extreme Software (CD version 4.2, 2Z691-5417-A), since then it worked fine.
The LAN is managed by a wireless router from Italia Telecom (I live in Turin), here are some specs of the router :
Alice Gate 2+ (http://aiuto.alice.it/informazioni/m.../alice_w2.html),
- standard ADSL (these refer to the Italian telecom compliance)
- ITU G.992.1/2/3/5 Annex A
- ANSI T1.413
- Protocols :
- RFC 2516 PPP over ethernet
- RFC 2684 - formerly RFC 1483 and RFC 2364
- Support for ATM UNI3.1, UNI 4.0
- IPTV functionality via Port mapping
- OAM F4/F5 Loop Back
- Interfaces :
- ADSL Interface, connection RJ11
- USB interface full speed (12 MBPS), connection B type, compatible USB rev 1.1
- Ethernet Interface, RJ45 connection, compatible with IEEE 802.3 10/100 Base T auto sensing
- WIFI IEEE 802,11/g Interface :
- max speed transmission 11/54 MBPS
- encrypting with key :
- WPA with pass word of 24 ASCII characters (WPA PSK 256 bits key)
- WEP of 128 bits (13 ASCII characters)
- supports WiSeConf (TM)
THANK YOU for any help, I would hate to have to switch back to Tiger...

Answer 1

I have the same self-assigned IP address problem on an old ibook which is connected to a Netgear modem via a Time Capsule. The problem occurs on waking from sleep and less often on startup. It's transient, but has been becoming a lot more frequent. Since it's limited to one of the four machines that connect to the network, I've been assuming it's about that computer and not the time capsule or the modem.
I've tried the fixes listed above (assigning a manual address, deleting preference files etc) as well as a few others (deleting the relevant passwords from the keychain and re-entering them in the hope that it was at that point the problem was occurring) and none of them have solved the problem.
I then came across a suggestion in another thread about this problem suggesting it might be the firewall. So I tried turning off the firewall (which is set to allow access for specific services and applications) and voila, the ibook received its IP address as it should the next time it woke from sleep. I tried putting it to sleep a few more times and waking it, as well as restarting it and repeating the procedure, and each time it worked, which was interesting.
Obviously having a computer with no firewall is not a great solution though, so I turned the firewall back on, and this is where it gets interesting. Because since turning it back on the problem seems to have stayed fixed.
I'm not enough of a techie to know what this might mean, but it might also be worth mentioning that the ibook throws up a pile of annoying incoming connection requests every time you start up - do you want to allow kp-something-something access etc etc, and a little while back I tried to stop this by creating an allow incoming settings for the kp-something-something request (since I've now deleted it I don't remember exactly what it was, but it's something other people have complained about). This didn't work, and I actually deleted the line in the list of File sharing (AP) settings while I was in the firewall settings trying to fix this problem. Even more interestingly, since I turned the firewall off and on again these requests on start up seem to have stopped.
I also have a suggestion for anyone who can't get the firewall trick to work, which is disable the password access for your machine and add use MAC address filtering on your router to try and get in that way. I don't know if this will work, but it might . . .