Evolution broken following upgrade: default key ring locked.

I have just upgraded Ubuntu 8.10 with the automatic online updates. Evolution now gives me a message I have not seen before saying that the default keyring is locked and asks for a password, which I believe I have not set. It fails to remember the passwords for my e-mail accounts, though I can enter them again by hand each session (by repeatedly pressing Deny when it asks for the keyring password).

It may be relevant that there is a broken lock in the Mozilla folder, which refers to a website that it says does not exist.

I am new to Ubuntu and one of its attractions was that I could learn about it at leisure while it just worked for daily tasks. As yet, I do not know enough to sort out this problem. Any help or explanation would be appreciated.