Keychain problems



A while ago i updated my installation of Mac OS X 10.4 tiger and after I did it it popped up a message on startup saying that Airport has been upgraded would i like it to use my existing key chain entries bla-bla, so i click "No Change" and i works fine. the problem is thta every time I start the machine it asks the same question and it is getting rather annoying now.

does anyone have any ideas as to what this could be and how i could fix it?

Many Thanks