For a number of third party wireless access points, AirPort 3.3 (released earlier this month) will not allow entry of a WEP key in the drop-down AirPort network selection menu, forcing users to enter the WEP key via "Internet Connect'" instead.
Sally Shears, along with a handful of other readers, reports that after applying the version 3.3 update and attempting to select the access point in the universal AirPort menu (displayed as a signal strength indicator), she cannot paste into the "password" text area and if she tries to type in the password, the "OK" button stays gray.
So far the issue has been reported with some 3Com routers, but appears to affect a variety of non-Apple access points.
The work-around is to open internet connect where the password dialogue works as expected.
Shears explains how the problem manifests, and how to enter the WEP key through Internet Connect.
"Set up the router. You'll want a WEP key. Turn on WEP... 128-bit... Generate a key which will be 26 hex digits.Select and copy it to a safe place; you don't want to have to type this. Don't forget to change the router password! [...] Now try to connect wirelessly... I could select the access point in the menu-bar drop down, but NOTHING, NO-WAY could I enter the 26 hex characters for the WEP key. In particular, I could not paste! I think the drop-down menu is broken, so we'll have to do it another way. With Internet Connect.
"In the Airport drop-down, select "Open Internet Connect"... Then select the access point from the list. You'll get a "requires password" dialogue... Pick "WEP 40/128-bit hex"... Paste the 26 char key in the "Password" block... Click OK. Now you should be connected. The next time, do the same thing, but check the box "Add to Keychain" Save the SSID and 26 character WEP key in a text file somewhere so you can find it. Also, don't lose the router password you've set."