OS 9 can't do "WEP passwords" very well. Is your base station a genuine AirPort base station, or is it 3rd party? If it's 3rd party, the password can't be used in OS 9. You'll have to find the hex key and supply that in OS 9 when prompted for a "password." Enter "0x" (that's zero ecks) and then your hex key.

For instance, if your hex key were 1234abcd0f, you would enter "0x1234abcd0f".

Peace,

Drew