This is an old revision of the document!
If you are using a WEP encryption ensure you use only lower case letters.
If you are using WPA encryption, all letters are case sensitive and you must include spaces if there are any in your pass phrase. Please verify you have typed in your pass phrase correctly.
If you see either of the following errors, you've more than likely mis-typed your security key.
or
If either error appears, disconnect from the WiFi network, then reconnect and try retyping your key.