"Wireless Network has been compromised"

When I am on my G4 PB, my wireless often goes down, telling me"The wireless network appears to have been compromised and will be disabled for about a minute." In fact, it just happened.

So I find the network again and reconnect. Annoying, but not tragic. But again, still annoying. My iMac is also connected through wireless and has never had that problem. Is it just the card in my PB starting to go?

Thanks,

dan