Found on a IBM R40 (Kudos on the quality of the laptop support! Keep it up!):

(From memory) During the configuration of WEP keys for the built-in wireless hardware, after entering the first key, click the button to bring up the additional keys window. The key length defaults to 128. If a key of an incorrect length is entered, the window apparently freezes. What has happened, however, is that an *untitled* error dialog box has come up UNDERNEATH the previous window. This dialog can only be reached by alt-tabbing to the untitled window (looks like a blank bar in alt-tab).