According to [link|http://groups-beta.google.com/group/comp.sys.mac.system/msg/235008791ce8bd4a?dmode=source|this]. Sorry I can't test it at the moment.

It might have something to do with the user settings and such. [link|http://www.apple.com/macosx/features/fastuserswitching/|Here]:

The Accounts panel in System Preferences makes it easy to manage security levels of multiple accounts. You can set passwords, user pictures, security levels and limitations for different users. The Accounts panel also lets you enable or disable Fast User Switching and choose a user account for automatic login.

Luck!

[edit:] <Carnac>Then again, maybe it has something to do with your WEP keys.</Carnac>

Cheers,
Scott.