Q: Keychain corrupt, what to do

See if this helps...

Mac OS X 10.4 Help, I forgot a password in my Keychain

http://www.askdavetaylor.com/recover_wifi_password_mac_os_x_107_lion.html

http://docs.info.apple.com/article.html?path=Mac/10.4/en/mh1960.html

Mac OS X 10.4: Keychain Access asks for keychain "login" after changing login password...

http://support.apple.com/kb/HT1631

Mac OS X 10.4 Help, I forgot a password in my Keychain

http://docs.info.apple.com/article.html?path=Mac/10.4/en/mh1960.html

Open Keychain Access in Utilities, use Keychain First Aid under the Keychain Menu item, then either check the Password under that item, change it, or delete it and start over.

Resetting your keychain in Mac OS X...

If Keychain First Aid finds an issue that it cannot repair, or if you do not know your keychain password, you may need to reset your keychain.

http://support.apple.com/kb/TS1544