AirPort Express cannot connect in client mode when encryption used

Question

I'm trying to set up my brand new AirPort Express in client mode to stream my music wirelessly to my receiver, which is on another floor of my house. I can't get it to associate with my Linksys WRV200 wireless router when using any kind of encryption. It works fine with encryption disabled, but I really don't want to leave that kind of security hole in my network.
-Equipment-
AirPort Extreme - v6.3 firmware
AirPort Admin - v4.2
WRV200 - v1.0.12 firmware (latest version)
Dell desktop with Windows XP SP2 (Running iTunes 6.0.5.20)
Dell laptop with Windows XP SP2 (running AirPort Admin)
IBM laptop with Fedora Core 5 (for connection testing)
-Procedure-
Various encryption methods were set on the WRV200's primary SSID and matching settings were set on the AirPort. All changes to the AirPort Extreme were done wirelessly with AirPort Admin 4.2 on Windows XP SP2+latest updates. Here are the changes from default that I made on the AirPort:
AirPort Tab
-Name and password were changed
-Wireless mode was set to "Join an existing wireless network (wireless client)"
-Network name was changed but stayed consistent throughout the tests
-Security setting was changed for each test
Internet Tab
-DHCP or manual IP were specified depending on the test.
Music Tab
-"Enable Air Tunes" was checked
-A name was given to the share
-Results-
No Encryption - iTunes sees the AirPort Extreme and can stream music to it. This works in both DHCP and manual IP mode. Interestingly enough, when set to DHCP, it grabs the same address as the manual one I input, which isn't the next one in sequence for the DHCP server (192.168.1.250 instead of 192.168.1.103)
128 bit WEP - Flashing orange light on the AirPort, no DHCP lease, no connection. Still doesn't work when a manual IP address is provided.
WPA2 Personal - Solid green light for 10 seconds, then two amber flashes and back to solid green. I can see association requests in my router's log every 10 seconds or so while this is going on. The strange light pattern only happens when a manual IP is selected. I still see the association requests when DHCP is selected, but the light on the AirPort just flashes amber all the time.
I know that the router's working correctly as my Linux and Windows laptops can DHCP and connect to the Internet with WEP or WPA2, but for some reason I can't connect the AirPort Express to the wireless router when I use encryption. I'd switch out the Linksys box, but I don't know of any other consumer-level wireless routers that allow multiple simultaneous wireless SSIDs.
Does anyone have a suggestion of what to try next?
AirPort Express   Other OS  

Answer 1

One of the problems with WEP is that the actual standard relies on a 10 character HEX key for 40bit WEP and a 26 character HEX key for 128bit WEP.
In order to make things easier for people, vendors use certain algorithms to convert simple alphanumeric passwords (or passphrases) into HEX keys, thus enabling people to use simple memorable WEP password rather than lengthy HEX keys.
The problem is that different vendors use different algorithms to generate the HEX key and therefore a ASCII password on an AEBS will be hashed differently on a Netgear client and vice versa.
One thing is a 13 character 128 bit WEP password will be hashed by all vendors in the same way (if you use 40bit WEP then a 5 character password is required).
Though sometimes not even that works and the HEX key must be used regardless.
AirPort: Joining an encrypted wireless network
http://docs.info.apple.com/article.html?artnum=106424
Choosing a password for networks that use Wired Equivalent Privacy (WEP)
http://docs.info.apple.com/article.html?artnum=108058